Races of the Mass Effect universe

This article is about the fictional races found within the Mass Effect universe. These races are explored in the novels Mass Effect: Revelation and Mass Effect: Ascension, and the video games Mass Effect, Mass Effect Galaxy, Mass Effect 2 and Mass Effect 3. Other than the following, there is also mention that dozens of other intelligent races are known to Citadel space and the galaxy; these races are left unidentified, but new races may appear in subsequent storylines.

Citadel races
The Citadel houses the main governing body of the Milky Way galaxy; its seat of power is an immense space station and the heart of galactic civilization that resembles an O'Neill cylinder, although there are no windows and atmosphere is only kept to around seven metres. The "land" sections are made up mostly of large buildings reminiscent of a city. Its head section is a Stanford torus, housing the headquarters of political and strategic decision-making. A second station, "Jump Zero," is mentioned but not yet seen in the franchise, and is described as a Bernal Sphere. Of the dozens of sentient races across the galaxy, the vast majority of Type II Civilizations recognize the authority of the Citadel and its ruling Council. The Council's duties include regulating trade and keeping the peace between the member races of Citadel space. All races keep their own form of sovereign government and the Citadel Council generally does not interfere unless in matters that affect the galaxy as a whole.

The Citadel Council consists of the three most influential races in the galaxy: the asari, salarians, and turians. The asari and salarians were the founding members of the Council, and the turians are the most recent race to achieve a Council seat. Depending of the player's choice near the end of Mass Effect, either humanity may be granted a seat on the Council, or the Council is reformed by the Alliance to include only human seats.

Asari
The asari are an all female humanoid race that hold one of three permanent seats on the Citadel council at the start of the game. In modern times, the asari normally act as the diplomatic arm of the Citadel Council.

A typical asari individual varies among blue, teal, or purple complexion; some asari have facial markings, which are unique color patterns that vary for every asari. Some of these facial markings are associated with eyebrows, freckles, or tattoos by humans, but the asari do not think of the markings as such themselves. In the place of head hair, asari possess semi-flexible, cartilage based scalp crests that grow into shape.
 * Asari Biology

All asari are biologically mono-gendered, although they display, from a human point-of-view, female characteristics and maternal instincts, with the ability to bear and nurse children. Liara states that concepts of male and female have no real meaning for her species, and, if asked, says that she is not precisely a woman. The asari are sexually female, and not asexual like single-celled life, and could be considered xenophilic and pansexual, as not only are they indiscriminate in regards to the races and genders of their mates, but prefer to mate with other races and sexes, believing that the genetic and racial traits of other species, when combined with asari genetic make-up, is of benefit to the asari race as a whole. Their dual reproductive and nervous systems allow them to mate with any species or gender, with whom the offspring is always another asari. Lines of descent are matrilineal. The asari are capable of participating in and enjoying physical sexual contact, but such recreational activities offer no reproductive value. To produce offspring they form a neurological connection with their partners, and by doing so draw genetic material, resulting in an offspring that is primarily asari in genetic makeup, however may possess recessive traits from the "father" species.

During melding, an asari consciously attunes her nervous system to her partner's, sending and receiving electrical impulses directly through the skin; effectively, the asari and her partner briefly become one unified nervous system. This unique means of reproduction is the reason asari are all talented biotics; their evolved ability to consciously control nerve impulses is very similar to biotic training. The partner can be another asari, or an alien of any gender. This reproductive process has led to confusion among non-asari, who might expect offspring with "mixed" genes. Asari do not draw genes or mix it with their own (an asari can never inherent a krogan "father's" resistance to diseases); they provide to copies of their genes, and any inheritance of traits, or even personality, is an urban legend. The offspring is pure Asari with no alteration to their species, even though "father's" DNA may or may not influence randomization. Conversely, they tend to attach a stigma to those born "pureblood" between two asari, as they believe that nothing is gained when two asari procreate (although most are too polite to openly speak of their prejudices). The mating of two asari also seems to increase the chance that the offspring will be an Ardat-Yakshi, a sterile individual with a genetic disorder that kills mates during melding, rather than a gentle linking of nervous systems.

In Mass Effect 2, a conversation occurs between a human, a salarian, and a turian who are watching an asari dancer. The men debate whose species the asari most resembles. Upon each forwarding their own race, the human theorizes that the asari might be using mind control to appear attractive to other species. It is more likely that the three men were merely focusing on characteristics their species shares with the asari (e.g., body shape for humans, skin color for salarians, head fringe for turians). All three men compliment the asari's flexibility and grace. This conversation implies that asari are considered attractive to many species and genders, which would prove useful considering their method of reproduction. Mordin Solus postulates that the asari's cross-species attraction may be neurochemical in nature.

The asari can live for a thousand years, going through three stages in life; the Maiden stage (lasting to 350 years), an energetic phase in life in which an asari is considered a youth and setting the initial course of its life; the Matron stage (lasting from 350–700 years) where an asari draws back to a more deliberative phase and begins to lay the foundations of a family and its place in society (though some asari have been known to start families as early as 100 years old), and finally the Matriarch phase (700-1,000 years) where the asari takes its place among the elite in society, participating more in cultural and political affairs and generally leading the next generation to fruition. Each stage can be started whenever an asari feels that she has reached the correct level of maturity. While each stage of life is marked by strong biological tendencies, individuals do make unexpected life choices. For example, there are Maidens who stay close to home rather than explore, Matrons who would rather work than build a family, and Matriarchs who have no interest in community affairs.

The asari were the first contemporary race to achieve space-flight and discover the mass relays. When they found the Citadel in around 580 BCE, the asari also encountered the keepers, whose mute assistance enabled them to quickly settle on the station and learn how to operate its systems. Sixty years later, the salarians made first contact with them, and together the two species agreed to found the Council. The asari continued their exploration. In around 200 BCE, the asari made first contact with the elcor and played a key role in their ascension into the galactic community. It is known that they were charting the Gorgon system at some point in Earth's 17th century.
 * Asari History

Along with her guides Janiri and Lucen, Athame is credited for helping to bring enlightenment to the ancient asari, with Janiri teaching them agricultural practices (including the seasons), Lucen teaching them about the stars, and Athame teaching them mathematics and medicine. The ancient asari also believed that Athame protected their homeworld Thessia from attacks by other, jealous gods. In the Temple of Athame on Thessia, it is revealed that the asari owe their high level of technological advancement to a Prothean VI, Vendetta. This information is kept highly classified by the asari government, as it would discredit the virtually universal belief that the asari became the most powerful race in the galaxy on their own merit. When examining the artifacts in the asari temple, Javik comments on asari development. According to him, the "goddess Athame" was in fact a Prothean. The Protheans protected the asari from an asteroid strike at some point in history. They also defended the asari from a race known as the oravores, who wanted to exploit Thessia for its vast resources. Furthermore, they were responsible for every asari having biotic abilities by shaping their genome.

Of all the species in Council space, the asari are the most widespread, powerful, and respected, due in part to their being the first species since the Protheans to achieve interstellar flight, to discover and learn how to use the Citadel, and their position as a founding member species of the Citadel Council. Despite this, the asari are open in their service to others, to the point where there is no cultural stigma attached to performance arts, even sexual ones. This has led to salacious rumors of asari promiscuity, which they consider unfounded. Because of their long lifespan, asari tend to have a "long view" not common in other races. When they encounter a new species or situation, the asari are more comfortable with an extended period of passive observation and study than immediate action. They are unfazed that some of their investments or decisions may not pay off for decades or centuries. Matriarchs can seem to make incomprehensible decisions, but their insight is evident when their carefully-laid plans come to fruition. In interstellar relations, this long view manifests in the unspoken policy of centrism. The asari instinctively seek to maintain stable balances of economic, political, and military power.
 * Asari Culture

Of all the galactic species, the asari are the most economically powerful; their culture, products and entertainment dominate the galaxy. They are governed by a loose democracy, known as the Asari Republics, and are known to be politically centrist, favoring stability that is conducive to cultural and economic development. Politically, they practice a form of direct democracy that could only be described as an e-democracy, where citizens contribute to the general consensus via a huge interconnected network. However, they also have a matriarchal council that heeds the will of the people and make decision for their welfare accordingly. Traditionally, asari spread their influence through cultural domination and intellectual superiority. They invite new species of advanced development to join the galactic community, knowing that their ideals and beliefs will inevitably influence the existing culture. The asari tend toward communal, consensus attitudes among themselves too: for example, they prefer to live in shared spaces aboard starships even if there are alternatives available.

In Mass Effect: Revelation, David Anderson admits that, when dealing with the asari, despite their political and military prowess their feminine appearance makes it difficult for him to accept them as one of the most powerful races in the galaxy. He feels that this isn't his fault due to thousands of years of human cultural bias. Asari are well aware they tend to be attractive, and are comfortable expressing their sexuality, as witnessed with asari erotic dancers, and many young males and females of all races tend to have a fascination with asari. As a result of the age difference, and the social matrifocal family structure, many asari raise their daughters alone, especially if the "father" species is short-lived. Despite their partner's death, a part of them will live within their other. Asari accept that they will almost inevitably outlive their partner (with the notable exception of the krogan, who have a similarly immense longevity). They apply their philosophical "long view" to relationships as well, savouring the time they spend with their partners rather than focusing on their inevitable loss.

The pantheistic mainstream asari religion is siari, which translates roughly as "All is One." The faithful agree on certain core truths: the universe is a consciousness, every life within it is an aspect of the greater whole, and death is a merging of one's spiritual energy back into greater universal consciousness. Siarists don't specifically believe in reincarnation; they believe in spiritual energy returning to the universal consciousness upon death will eventually be used to fill new mortal vessels. Siari became popular after the asari left their homeworld and discovered their ability to "meld" with nearly any form of life. This ability is seen as proof that all life is fundamentally similar. Siari priestesses see their role as promoting unity between disparate shards of the universe's awareness. Before the rise of siari pantheism, asari religions were as diverse as their political opinion. The strongest survivor of those days is the monotheistic religion worshipping the goddess Athame. The Athame Doctrine is an asari religion founded on the worship of the goddess Athame. In ancient times, Athame was a goddess of prophecy and fate, and the matriarch of the asari pantheon. Like the asari, the goddess cycles through the triple aspects of maiden, matron, and matriarch. Asari often swear "by the goddess", though this may be a cultural legacy rather than reflecting an individual's belief. Worship of Athame gradually changed, becoming the basis for a monotheistic religion that oversaw all stages and roles in asari society, and eventually fell out of favor as the asari turned to the siari religion.

The Temple of Athame on Thessia still stands as a reminder of the influence that Athame worship had on asari culture. The temple displays various relics attributed to Athame, including murals, busts of Janiri and Lucen, Athame's sword and shield, and fragments of the Athame Codex, an ancient text that explains how asari learned mathematics and agriculture. Other relics not kept at the temple include the Rings of Alune, which were worn by an asari who was believed to have been taught medicine by Athame herself. As an homage to the goddess, three of the planets in the Parnitha system, the asari's home system, are named for Athame, Janiri, and Lucen.

Their homeworld of Thessia, known as the Asari Republics, is composed of an interconnected system of city-states, similar to those of ancient Greece; the asari came late to the notion of world government. For centuries, their homeworld of Thessia was dotted with loose confederacies of great republican cities. Since the asari culture values consensus and accommodation, there was little impetus to form larger principalities. Rather than hoard resources, the asari bartered freely. Rather than attack one another over differing philosophies, they sought to understand one another. Only in the information age did the city-states grow close; communication over the internet evolved into an 'electronic democracy'. Aside from their Council representative, the asari have no politicians or elections, but a free-wheeling, all-inclusive gynocentric legislature that citizens can participate in at will. Policy debates take place at all hours of the day, in official chat rooms and forums moderated by specially-programmed virtual intelligences. All aspects of policy are open to plebiscite at any time. In any given debate, the asari tend to lend the most credence to the opinions of any Matriarchs present, nearly always deferring to the experience of these millennia-old 'wise women'.
 * Asari Government

The asari military resembles a collection of tribal warrior bands with no national structure. Each community organizes its own unit as the locals see fit, and elect a leader to command them. Units from populous cities are large and well-equipped, while those from farm villages may be only a few with small arms. There is no uniform; everyone wears what they like. The asari military is not an irregular militia, however; those who serve are full-time professionals. The average asari warrior is in the maiden stage of its life and has devoted 20–30 years studying the martial arts. Asari choose to be warriors at a young age, and their education from that point is dedicated to sharpening their mind and body for that sole purpose. When they retire, they possess an alarming proficiency for killing. Warriors fight individually or in pairs, depending on the tactics preferred in their town. One-on-one, a warrior is practically unbeatable, possessing profound tactical insight, a hunter's eye, and a dancer's grace and alacrity. Biotics are common enough that some capability is a requirement to be trained as a warrior; lack of biotic talent excludes a young asari from military service.
 * Asari Military

While fluid and mobile, asari can't stand up in a firestorm the way a krogan, turian, or human could. Since their units are small and typically lack heavy armor and support weapons, they are almost incapable of fighting a conventional war, particularly one of a defensive nature. So asari units typically undertake special operations missions. Like an army of ninja, they are adept at ambush, infiltration, and assassination, demoralizing and defeating their enemies through intense, focused guerrilla strikes. Asari warriors were among the first individuals to be chosen as Spectres and played a key role in the Krogan Rebellions. As a popular turian saying puts it, "The asari are the finest warriors in the galaxy. Fortunately, there are not many of them."

Drell
The drell are a race of reptile-like humanoids that appear in Mass Effect 2.

The drell ancestors emerged from dry, rocky deserts on the barren world of Rakhana. Drell are omnivorous reptile-like humanoids with an average lifespan of 85 galactic standard years. Drell appearance is very similar to asari and humans, but their muscle tissue is slightly denser than that of humans, giving them a wiry strength. Many of their more reptilian features are concealed, however one unique characteristic is the hyoid bone in their throats, which allows them to inflate their throats and produce vocal sounds outside of the human range. Since the drell ancestors emerged from arid, rocky deserts, the humid, ocean-covered hanar homeworld of Kahje proved tolerable only when the drell stayed inside a climate-controlled dome city. A significant number of drell, including Shepard's teammate Thane Krios, suffer from a condition called Kepral's Syndrome; this syndrome erodes the ability of drell lungs to take in oxygen, and eventually spreads out to other organs. The illness is caused by the inability of drell physiology to adapt to long-term habitation in conditions more humid than their native world. While the hanar are funding a search for a cure, the illness is fatal and incurable during the course of the games. Every drell possesses an Eidetic memory, allowing them to recall any past events in outstanding detail; an adaptation to a world where they must remember the location of every necessary resource (vegetation, drinkable water and prey migration paths) across vast distances. The memories are so strong that an external stimulus can trigger a powerful memory recall. These recalls are so vivid and detailed that some drell may mistake it for reality. Thane Krios, for example, remembers every assassination he has ever performed and can describe them in flawless detail, and says he prefers to spend a lonely night with the perfect memory of another. This process can be involuntary.
 * Drell Biology

Rapid industrial expansion and overpopulation produced disastrous results 800 years prior to the events of the Mass Effect series, when the already arid planet began the descent to lifelessness. At the time, the drell lacked interstellar flight capacity and faced imminent extinction until first contact was made with the hanar. Over the next ten years, the hanar transported hundreds of thousands of drell to the hanar world, Kahje. The remaining billions left on Rakhana perished on their dying planet, warring against each other for diminishing resources. The drell now thrive co-existing with the Hanar and have been a part of galactic civilization for roughly two centuries. The debt of gratitude that the drell owe the hanar is referred to as the Compact, which the drell fulfill by taking on tasks that the hanar find difficult, such as combat. Any drell may refuse to serve, but as being requested to serve is a great honor, few turn down the offer.
 * Drell History

Most drell are content to live on Kahje. They are afforded every opportunity to thrive by the hanar, yet some outsiders and even some hanar regard the drell as second-class citizens. However it is quite the opposite, as they have integrated themselves into every level of hanar society as respected, productive citizens. A few, solitary drell travelers often seek out new species elsewhere, and in turn adopt that species' culture. Such drell number in the thousands, and are scattered across the galaxy, tending towards quiet, integrated lives. Some drell grow a close, personal relationship with the hanar. So much so that the hanar will even tell the drell their "Soul Name". Drell have adapted to communication with hanar by getting implants in their eyes to allow them to observe the bioluminescense the hanar use for communication. Drell such as Thane are able to see ultraviolet light as a silvery color, though lose differentiation between colors at the opposite end of the spectrum, such as the difference between dark red and black.
 * Drell Culture

Most drell are deeply religious, believing that they have souls separate from their bodies. They see death as a departure from the body, and they also state that a person's body and soul form a Whole. When the soul is traumatized or otherwise disrupted, or the body is ill or injured, a person is no longer Whole. They also believe that their body can be directed as a separate entity from themselves, in the case of Thane Krios taking no responsibility for his numerous killings, which were ordered by the hanar. The drell religion is also polytheistic, with the drell having multiple gods whom they pray to in varying situations. This religion included at least three gods: Amonkira, Lord of Hunters; Arashu, Goddess of Motherhood and Protection; and Kalahira, Goddess of Oceans and Afterlife. Many of the older traditions of the drell have begun to die out. The younger generations no longer believe the old ways of their ancestors can help them now, with so many other ways to interpret one's place in the universe. Many drell have embraced the hanar Enkindlers or the asari philosophies.

Elcor
Elcor are large, elephant-like aliens that speak in a slow, monotone fashion.

Elcor evolved on Dekuuna, a large terrestrial world with consequently formidable gravity, forcing them to become extremely deliberate with their movements — any minor stumble could result in injury, if not death. Their large, heavy bodies are incapable of moving quickly, but they possess a rather imposing stature and immense strength, as well as thick, tough skin. They move using all four limbs to support and balance their massive bodies; their walk is thunderously loud within Earth-like gravity environments. This physical necessity therefore resulted in a political, social, and cultural philosophy that extolled the virtues of caution, deliberation, and patience. The elcor have highly-attuned olfactory senses., using pheromones, subvocalized infrasound and subtle body movements, rather than tone, to convey meaning and intent when conversing. The elcor found that when they encountered other races, these subtleties were lost on them; because of this, elcor choose to describe their emotions before making any statements, and today have computerized translator programs which do this automatically; Elcor speech is heard by most species as a flat, ponderous monotone.
 * Elcor Biology

Prehistoric elcor traveled across Dekuuna in large tribal groups. These groups were led by the eldest and most experienced elcor matriarchs. This may have later developed into the elcor culture of Elders, whose wisdom could keep the tribe safe provided they followed the correct guidance (see below). According to their ambassador, the elcor were just making their first forays into space travel when the asari made contact with them. With their help, the elcor discovered the closest mass relay and, within a single lifetime, had established a regular trade route to the Citadel. The elcor quickly became one of the more prominent species in Citadel space, though they still have to share an embassy with the volus.
 * Elcor History

After the destruction of the elcor navy, Reapers moved in their ground troops to occupy the cities. This has taken longer than most civilized worlds, as the elcor have spread out into smaller, distant settlements, reflecting their preference for close-knit family communities instead of densely packed cities.

The elcor homeworld Dekuuna overflows with natural resources protected by law, from large deposits of precious metals to vast forests. The elcor themselves live in rich grasslands near the equator. The majority of Dekuuna settlements are tucked within this belt, as the conservative elcor feel little desire to build outside their comfort zone. Their twin capitals are for migrations from the wet season to the dry season, a tradition made obsolete by modern technology but still observed.
 * Elcor Culture

Elcor usually prefer to stay on their colonies rather than travel in space, which may be why few elcor are seen on the Citadel or on other worlds. Possibly because of their size or evolution in the open air, the elcor find the necessary confines of space travel uncomfortable. Evolving in a high-gravity environment where a fall could be lethal has made elcor psychology deeply cautious and conservative. Their culture is built on small, tight-knit groups, and their conservative nature means the elcor government is extremely stable. Despite this, they are always welcoming to outsiders. The elcor economy is small, only slightly larger than the Alliance's, but extremely well developed. They see no point to rushing things, and are fond of making thorough, century-long development plans. They don't need to trade for any resource—they have all they require to supply their own needs, and trade only in finished goods. Any attempt to embargo their space would be fruitless.

The elcor's main political body, the Counts of Dekuuna, demonstrate this tendency in their political decision-making process; their millennia-old archives are constantly kept up-to-date and are constantly consulted by the Counts when making decisions to ensure that precedent is respected and all options are kept in consideration. As such, the Counts spend years poring over ancient records of jurisprudence to determine the precedent that should be followed in any given situation, in making decisions or enacting laws, sometimes taking decades to decide on relatively simple matters of state. The Elders record closely argued and minutely detailed instructions on what course to follow in any theoretical crisis. These are filed away in huge libraries of data discs and are consulted when needed. This makes elcor policies very predictable, provided one has done a great deal of research.
 * Elcor Government

Though large and physically powerful creatures, they are rarely violent; their slow-movements and conservative psyches makes elcor unsuitable for spur-of-the-moment decisions necessary in combat situations. However, if pressed into violent situations, their extremely thick hides make them nearly invulnerable to conventional weapons and their extraordinary strength allows them to carry various amounts of heavy weaponry and commensurate ammunition with ease. The elcor mount weapons on their back that are automated and controlled by onboard VI processes. These war machines can choose between thousands of gambits developed and polished over centuries by elcor strategists. They have been referred to as "living tanks."
 * Elcor Military

The elcor do not maintain a large space fleet. While as a race with an embassy on the Citadel they are technically allowed to build a single dreadnaught (as the Volus have done), they did not bother to build one, as they rarely become involved in major wars.

Hanar
The hanar are a race that resemble jellyfish, with a gelatinous body (often pink-skinned) and tentacles hanging beneath.

The hanar homeworld, Kahje, has 90% ocean cover and orbits an energetic white star, resulting in a permanent blanket of clouds. Hanar stand slightly taller than a human and have three fingers at the end of each of their tentacles. Having no physical means of verbal communication, they converse with each other using sophisticated bioluminescence (which modern translators will automatically render into something that can be understood by other races). many drell apply genetic modification to their eyes in order to perceive higher frequency flashes which allows them to understand the hanar. Their speech is scrupulous precision and extreme polite and very eloquent. Being an oceanic invertebrate life-form, they cannot support their physical forms in standard gravity, instead using mass effect contra-gravitic levitation packs. Their bodies are 90% water content.
 * Hanar Biology

Hanar's extreme cultural obsession with politeness and protocol sometimes leads to problems interacting with other species, which may not understand their rules of etiquette and manners. As the majority of the hanar dominion is entirely self-sufficient and isolated, and thus trade and diplomatic relations are generally unnecessary, this tendency doesn't pose much of a problem with matters of intergalactic state or foreign affairs. However, any hanar who choose to take up residence on alien worlds or who man outposts that come into regular contact with alien races are advised to take special classes that help counter this tendency and smooth-over inter-species relationships. Few "Council-standard" technologies are available in their space, and they produce very few goods that are usable by others. However, in Mass Effect: Revelation, Edan Had'dah had a liking for hanar-produced liquors. This is likely to have been procured through the discreet gray-market trade relationships the hanar still maintain with the batarians, despite the latter species own political and economic isolation from the rest of Citadel space. Possibly due to their physical frailty, the hanar employ robo-miners to excavate valuable resources.
 * Hanar Culture

Several hundred years ago, the hanar made contact with the drell on their nearby homeworld of Rakhana. Drell society was quickly collapsing due to overpopulation and warring over scarce resources, so the hanar rescued several hundred thousand drell and brought them to Kahje, where they integrated into hanar society with the remaining drell dying out. Now the drell serve as a client race of the hanar, and although to outside observers the relationship can be construed as a form of slavery, the reality is very different. Drell have integrated with every level of hanar society, and most consider it an honor to serve a hanar family in a tradition referred to as the Compact. Many drell become unofficial members of the family, and some even earn the privilege to learn their masters' "soul names". Drell servants usually carry out hanar assassinations, as the hanar are too cumbersome out of the water to participate in a physical fight — though Zaeed Massani mentions that he was once nearly strangled by one. The drell assassin Thane also maintains that the hanar have a strong grip and possess strong natural poison.

Every hanar has two names: the "Face Name" and the "Soul Name". The face name is the name that is known to public and referring to oneself as anything more personal, such as "I" or the soul name, is considered egotistical. Among hanar, it is customary to refer to oneself as "I" or by one's Soul Name only among family or close friends; with others, "it", "this one", or the Face Name are used. Financial interaction with the galactic economy is limited, and hanar space has few facilities designed to provide bipeds with a means to operate equipment such as computer terminals, contact generally being limited to border trade stations.

Due to the presence of Prothean ruins on Kahje, the hanar have developed a religion centered on the ancient species, calling them the "Enkindlers". Hanar myths often speak of them as an elder race that uplifted and civilized them by teaching them language. The hanar practice a religious holiday called Nyahir or "First Cresting Bloom" which lasts a full thirteen days and revolves around celebrating the gift of speech, which they attribute to having come from the Enkindlers. It is a mixture of contemplation and competition, with the faithful engaged in stylized debates, poetry duels, and other traditional hanar art forms. The winners of these events have their names inscribed in bio-luminescence on the side of Mount Vassla, an underwater volcano at the heart of one of the oldest Prothean ruins on Kahje.

The hanar are governed by the Illuminated Primacy, a theocracy that worships the Protheans as mythological "Enkindlers", although they are tolerant of other species and the religious and spiritual creeds that they adhere to and espouse. For this reason, they have difficulty seeing the Protheans as an extinct biological species as most other Citadel races do, instead tending to view them as components of their religious mythology. According to gossip between a salarian and a turian in the Council Chambers, the hanar are considered likely prospects for a Council seat in the near future, though what great deed the hanar did for the Council to warrant consideration is not revealed. Other races sometimes see the hanar as elitist because of their intolerance for "incorrect" speech (and occasionally refer to them derisively as "jellies"). The hanar themselves are known to become vocal if their religious rights appear threatened in any way, which occasionally causes clashes with other Citadel races. A hanar on the Presidium steadfastly defends its right to preach about the Enkindlers in a non-proselytizing zone even when a C-Sec officer asks it to leave, and Commander Shepard hears a news story on the Citadel about the hanar blockading a Prothean ruin being excavated by the salarians.
 * Hanar Government

Given their nature, hanar have limited interactive abilities, and do not possess apparent means of combat or normal physical manipulation. Due to this, the hanar rely frequently on the drell, which the hanar saved from imminent extinction, as a client race (see above).
 * Hanar Military

Humans
Humans in Mass Effect are generally similar to those in modern day life.


 * Human Biology

Humans have a fairly robust physiology. Their internal makeup and reproductive processes are typical of most bipedal omnivore mammals, and their size and proportions give the appearance of being strong, fast and agile. In comparison to the Council races, physically fit humans are roughly on par with turians and less agile than asari, and slow-reacting to salarians. Biologically speaking, Humans reach reproductive maturity at approximately 13 Earth years of age, physical maturity at approximately 18 Earth years of age, and psychological maturity at 21 Earth years of age; at which point they have usually finished their academic education and either directly enter the workforce or begin training for a profession. Medical technological advances has raised the human lifespan to around 150 Earth years and have eradicated almost all known diseases and genetic defects that afflict them. Like most organic races, humans are also capable of producing biotic individuals but there is a high risk of medical complications. It has been noted that humans are unusual in the galactic community because they have far greater genetic diversity compared to other species with more peaks and valleys. This makes human genetic material useful in biological experiments, as a control group.


 * Human History

A recent addition to the galactic stage at the time of Mass Effect in 2183, human society advanced significantly with the advent of interstellar travel, made possible with the discovery of lost Prothean technology. Humans quickly expanded outwards and established more and more colonies on uninhabited planets. This rapid expansion brought them into contact with the turians, with whom they quickly came into conflict. The human-turian First Contact War in 2157 brought humans to the attention of the species of the Citadel Council. After the System Alliance's quick and effective military response to the turian occupation of the human colony of Shanxi, both sides began gearing up for full-scale war. The Citadel Council immediately stepped in and mediated an end to the conflict, granting humans considerable latitude in their colonization efforts, much to the dismay of the batarians, who abandoned their Citadel embassy in protest. In the decades since their appearance, humans have quickly risen to prominence, gaining an embassy on the Citadel and fueling resentful speculation from other races that humans will soon be given an invitation to become full members of the Council.

In 2148, human explorers on Mars uncovered a long-ruined Prothean observation post, with a surviving data cache that proved Protheans had studied Cro-Magnon humans millennia ago. The impact was profound in all areas of human culture, but nowhere more so than religion. New beliefs sprang up overnight such as the Interventionary Evolutionists, who zealously proclaimed the discovery as proof that all human history had been directed and controlled by alien forces. Even established religions struggled to explain extraterrestrial life; while religions tried to assimilate this discovery into their doctrine, a global rush began to decipher the petabytes of data from the outpost. Some tried to incorporate this new-found knowledge into their dogma, some remained silent, while a few tried to stubbornly deny the evidence found on Mars. The news of the discovery dominated the media and raised questions not only about the existence and purpose of humanity, but questions about the aliens themselves. Foremost, were they still out there? While these questions had served to fracture most religions, they had a unifying effect in politics. Rather than nations fighting each other over their differences, it was now "us vs. them" and the foundations of a united human front were laid. Within a year of the discovery, Earth's eighteen largest nations had drafted and ratified the Systems Alliance charter, establishing a representative political body to expand and defend human territory. Shortly thereafter, the various nations of Earth pooled their military resources to create the Systems Alliance Military. The same year, 2149, the Alliance discovered the Sol system's mass relay orbiting Pluto, previously thought to be a moon, Charon; explorers managed to open the Charon Relay and discovered it led to Arcturus. With the help of the fledgling Systems Alliance, humans expanded to other systems, opening any mass relays they could find.

The Alliance began a rapid campaign of expansion, establishing numerous colonies and constructing a large fleet, even though it had yet to encounter another species. Maintaining this expansion policy, the Alliance activated all the mass relays it could find to seek out new resources and possible colonies. But despite this success, the Systems Alliance was not considered a serious political body, as it was considered to lack the authority of individual nations. Eight years later, humanity made first contact with another alien species and everything changed. A scout fleet consisting of three frigates and two cargo vessels, trying to activate a mass relay, encountered a turian patrol fleet. Activating a dormant mass relay without knowing where it led had been declared illegal by the Council, though the humans did not know this. Only one of the human ships made it back to Shanxi colony, which was subsequently discovered by the turians and invaded. While individual governments remained unsure on what action should be taken, the Alliance took control and attacked the turians. The resulting First Contact War was relatively short and bloodless, lasting only months and costing 623 human lives (with a slightly higher number of turian casualties). The Citadel Council intervened and negotiated a peace. With the discovery of the Citadel and the greater community, humanity leaped onto the galactic stage. The Alliance received a surge of popularity, which gave it the necessary political credibility to establish its own Parliament and speak for humanity as a whole.

Humans first came to the attention of the galactic community after a brief but intense conflict with the turians, known by humans as the First Contact War, begun in 2157. The conflict began when the turians attacked a human fleet attempting to activate a dormant mass relay (illegal under Council law) and then occupied the human colony of Shanxi. Led by Admiral Kastanie Drescher, the Second Fleet then launched a massive counter-attack, which caught the turians by surprise and expelled them from Shanxi. The conflict caught the attention of the Citadel Council, which wasted no time brokering a peace, thus introducing humans to the galactic community. As a consequence of the Alliance's swift and decisive action during the First Contact War, the Alliance became the representative and supranational governing body of humanity. Since then, humans have rapidly risen in prominence. In 2165, humanity was granted an embassy on the Citadel in recognition of their growing power and influence in the galactic community. The timing of this achievement, less than a decade after first contact, caused some friction with other Citadel races who had waited decades for such recognition. Humanity continued to expand to unclaimed star systems on the edge of Citadel space, which eventually led to competition with the batarians. When the batarians tried and failed to convince the Council to declare the Skyllian Verge "a zone of batarian interest", they closed their embassy and withdrew from Citadel space. Viewing humans as the cause of their fall from grace, batarians frequently came into conflict with human colonies, especially batarian slavers. Tensions between humans and batarians persist for decades.

Since then, the Alliance has continued its expansion, with the resource wealth of a dozen settled colonies and hundreds of industrial outposts flowing back to Earth. This expansion brought the Alliance into conflict with the batarians as both species rushed to settle the Skyllian Verge, while maintaining a careful truce with the turians. The Alliance has also been granted an embassy on the Citadel. It has been speculated, given humanity's remarkably fast rise in terms of military, political, and economic power, that the Systems Alliance may soon be invited to join the Citadel Council. This has been a source of some concern to several other species. Humans have expanded rapidly from Earth in a very short period of time, becoming swiftly integrated into Citadel society and the galactic economy. They have become less ethnically diverse in the twenty-second century, due to a more multicultural society and greater unity between nations. Improved medical advances and gene therapy have led to longer, healthier lifespans; the average citizen can now expect to live to around 130. Most humans retain their native tongue, but learn alien languages or trade pidgin for the sake of convenience or as a gesture of unity. One of the lasting consequences of the First Contact War was the interruption of a period of relative peace in the galaxy. Fairly or unfairly, humans are often thought of as aggressors, and are sometimes portrayed as a disruptive influence by non-human media. At the same time, other races recognise humans as an adaptable, intelligent and militarily capable race.

In the 2160s, The Alliance's ambassador on the Citadel, Anita Goyle, tried to induct a human into the Spectres as a first step toward a seat on the Council. Lieutenant David Anderson was selected as a candidate for the position due to his exemplary military service. But Anderson's observer, Saren Arterius, sabotaged his mission and falsified a report to the Council on what happened. The Alliance cooperated with the turians to create a new stealth frigate, the SSV Normandy. The Normandy was commissioned in 2183 with Anderson as her captain. A Spectre, Nihlus Kryik, was assigned to the Normandy's shakedown run, supposedly to observe, though his true purpose was to recover a Prothean Beacon from Eden Prime. Humans were caught off-guard by the geth attack on Eden Prime, humanity's most prosperous colony, in 2183. Systems Alliance forces and the legendary Commander Shepard were involved in several operations against geth incursions into Alliance territory. The conflict between the Systems Alliance and geth later became known as the Eden Prime War, and culminated in the Battle of the Citadel, where a massive invasion fleet led by the flagship Sovereign tore through Citadel defenses. With the timely aid of the Alliance's Fifth Fleet, the geth were defeated. At the ending of Mass Effect, humans will be invited to join the Citadel Council if Commander Shepard chose to save the original council. If not, the humans will form an all-new council, consisting of either just humans or a multispecies one depending on Shepard's decisions and alignment. Thanks to their efforts in the Battle of the Citadel, humanity rises to a new level of prominence in the galaxy. Partly as a result of humanity's prominent new role in the politics of Citadel space, the Alliance has headed a coalition force to systematically hunt down pockets of geth resistance. Political experts from all species have been debating what humanity's ascendancy means for Citadel space. The two candidates for human Council chairman—Donnel Udina and David Anderson—are still being selected.

The rapid ascension to intergalactic status caused emergence of various anti-alien pro-human movements. While Terra Firma is just a political party calling for cultural independence, Cerberus is a shadowy organization led by an enigmatic figure called "The Illusive Man" that emerged after the First Contact War and promotes human interests above everything else. Its ultimate objective is to enforce human supremacy over the galaxy, regardless of the means necessary to achieve it. Cerberus's immense resources and contacts are sufficient to resurrect Commander Shepard and replicate the Alliance's most advanced warship at the beginning of Mass Effect 2. Characters in-game speculate on rumors that Cerberus was once a "black ops" branch of the Alliance itself, partially explaining its reach. Once joining forces to stop the Collectors during the events of Mass Effect 2, Cerberus and the crew of the Normandy become enemies during the Reaper invasion in Mass Effect 3, as each side has opposing views about how to deal with it. While Shepard intends to unite the galaxy to confront the Reapers, the Illusive Man plans to gain control over the Reaper technology to consolidate human dominance over all other races.

Sometime after the attack on the Citadel, the Normandy is destroyed by a Collector cruiser and Shepard was declared dead. Because of this, the Alliance came hammering down on the Commander's talk about the Reapers and tried covering it up. By 2185, the Alliance is still having trouble adjusting to its higher standing in interstellar policy. Less than two years after the Battle of the Citadel, contact with some human colonies in the Terminus Systems is lost. Investigations reveal that the colonies' inhabitants have completely disappeared, with no trace of what happened to them. The Systems Alliance does little to intervene; with no explanation for the disappearances, the Alliance is unable to prevent further incidents. Humans on fringe colony worlds perceive the lack of action as an unwillingness to aid them, and begin to harbor resentment against the Alliance. The Alliance tries to rebuild trust through goodwill efforts, such as providing Horizon with new anti-starship defense turrets, but suspicion lingers. The colony abductions cease just as mysteriously as they began. While the Alliance publicly blames the abductions on Terminus Systems slaver rings, the fate of the thousands of missing colonists is never conclusively resolved. If the Council is saved in the first game, a news report will reveal that the turians and Systems Alliance are moving closer to becoming peacekeeping partners patrolling hostile territory cooperatively. The codex will also reveal that the Hierarchy has been moving to have closer ties with humanity as well as humanity earning deep trust and respect for saving the Council. Conversely, if the Council is sacrificed and solely replaced by humans, the Hierarchy reveals it won't be respecting the Treaty of Farixen dreadnought limits and that the Asari Republics have ceded their defense portions to the turians. The human Council doesn't comment upon this. Aliens are also deeply resentful of humanity taking over the Council and want to return to the status quo according to Avina.

If Arrival is completed, the Alliance detain Shepard for the destruction of the Bahak system and its approximately 300,000 colonists, though the Defense Committee refrains from court-martialing the Commander, considering Shepard's knowledge of the Reapers. By 2186 CE, the Alliance became aware that the Reapers were making an incursion into their space. While Admiral Hackett began mobilizing the fleets, the Defense Committee consulted Shepard for advice on how to deal with the threat. Unfortunately, the Reapers plowed through the Alliance's defenses and conquered Earth within a matter of hours, as well as destroying Arcturus Station, taking with it Alliance leadership. The Alliance was forced to abandon Earth before returning with a combined allied fleet to retake it.


 * Human Culture

The homeworld and capital of humanity is entering a new golden age. The resource wealth of a dozen settled colonies and a hundred industrial outposts flows back to Earth, fueling great works of industry, commerce, and art. The great cities are greening as arcology skyscrapers and telecommuting allow more efficient use of land. Disease, pollution, and other social ills were on the decline thanks to technological advances and a wealth of resources from the colonies. Earth was an inspiration even to alien cultures, resulting in influence out of proportion with humanity's brief time on the galactic stage. Earth and her various colonies are still divided among separate city-states, nation-states, and world-states; though all are affiliated beneath the overarching banner of the Systems Alliance. While every human enjoys longer and better life then ever, the gap between rich and poor widens daily. Advanced nations have eliminated most genetic disease and pollution. Less fortunate regions have not progressed beyond 20th century technology, and are often smog-choked, overpopulated slums. Sea levels have risen two meters in the last 200 years, and violent weather is common due to environmental damage inflicted during the late 21st century. The past few decades, however, have seen significant improvement due to recent technological advances.

Humans are generally seen to be very intelligent, abnormally ambitious, highly adaptable, individualistic and thus, unpredictable. They have a powerful desire to advance and improve themselves, and do so with such assertion that the normally staid Council races have been taken aback by their restlessness and relentless curiosity. Their economy, while much smaller than any of the Council races, is very powerful relative to their size, and their military prowess is amongst the greatest in the galaxy, despite the fact that only 3% of humans volunteer for the Alliance military, a far smaller proportion than other races. Their ability to defeat the turians in the First Contact War demonstrated graphically the potential of human military strength and is therefore a subject of concern for many races, who fear the consequences of another human-turian conflict.

The Alliance has quickly become a key player in the galactic economy, with several large human corporations taking their market share. The Alliance economy, though growing, does not yet come close to that of the asari or turians and is only approaching that of the elcor. The Alliance and the turians have become large trade partners despite lingering animosity over the First Contact War. Although humans have claimed many systems in the Attican Traverse and the Skyllian Verge, many of them contain rich resources which have not been fully surveyed, so the Alliance Geological Service (AGeS) offers bounties to those willing to explore these frontiers. The Alliance's various national treasuries are linked to the Citadel's credit network.

The Reaper attack has put an end to any semblance of this former life. The great cities of Earth are storehouses of human DNA for the Reapers to harvest. Reaper gunships, capable of megaton-scale firepower, annihilated industrial centers in seconds. The militaries of Earth's disparate nation-states have retained only partial communication with the Systems Alliance fleets, leaving the planet's resistance efforts uncoordinated and vulnerable. The loss of the comm-buoy network has cut off Earth's economy from the rest of the galaxy, sending shockwaves across galactic markets—and a significant obstacle to receiving aid.


 * Human Government

The Systems Alliance is an independent supranational government representing the interests of humanity as a whole; supported by The United Nations of Earth that is, for all intents, its own political, governmental, and military entity; it controls and manages all off-world activities. The Alliance is governed by a parliament based at Arcturus Station, which also serves as the Alliance's capital; the Navy's fleet is headquartered at Arcturus Station, a strategically invaluable installation whose system contains several primary mass relays leading to human territory in addition to the secondary mass relay to Earth, and as such it is the most heavily defended sector. The Alliance is responsible for the governance and defense of all extra-solar colonies and stations.

The Alliance grew out of the various nation space programs as a matter of practicality. Sol's planets had been explored and exploited through piecemeal nation efforts. The expense of colonizing entire new solar systems could not be met by any one country. With humans knowing that alien contact was inevitable, there was enough political will to jointly fund an international effort. Still, the Alliance was often disregarded by those on Earth until the First Contact War. While the national governments dithered and bickered over who should lead the effort to liberate Shanxi, the Alliance fleet struck decisively. Post-War public approval gave the Alliance the credibility to establish its own Parliament and become the galactic face of humanity, and has had an embassy on the Citadel since 2165.

The Alliance is responsible for the governance and defense of all extra-solar human colonies, and represents humanity on the galactic stage. It is a supranational government, and is based on a parliamentary system, with the Alliance Parliament based at Arcturus Station. It is unknown if the representation is based on the population of member nations on Earth and the colonies, or if all nations and colonies involved receive the same amount of parliamentary members. The Alliance government is headed by a Prime Minister; as of 2186 this position was occupied by Amul Shastri. It is unknown whether the Prime Minister is an elected member of Parliament, or is appointed to the position. While the Alliance is a supranational government, the member nations retain their individual sovereignty back on Earth. Among the Citadel races, the Alliance is considered a sovereign nation and no other species has right of oversight into Alliance affairs.

Many other species dislike their sudden ascendancy compared to their status as relative newcomers on the galactic stage. Some species feel that humanity is overly expansive in its colonization efforts and aggressive attempts to advance its position in galactic affairs. It took other species centuries to achieve what humanity has done in decades. Humans have also been doing what the Council could not: colonize planets in the Attican Traverse, the Skyllian Verge and along the borders of the Terminus Systems, all volatile regions where the Council has little authority. Human forces came into minor conflicts with the batarians over the Verge, which the batarians had been attempting to colonize themselves. When the batarians asked the Council to declare the Verge a "zone of batarian interest", they were refused; in response, the batarians became a rogue state, blaming humans for depriving them of valuable resources, and human-batarian relations have been hostile ever since. Unlike many species in Citadel space, humans have no close allies among the other races, though they are trade partners with the turians and asari. Without alliances or key political positions, humans have had to follow the edicts of the Council without having much influence on their decisions. Human ambassadors finally had their wishes answered when Shepard was admitted into the Spectres, the Council's elite operatives, and even further when they were given a seat on the Council, after either having saved them from the Battle of the Citadel, or having Humanity rebuild the Council when they were lost. However, now that Humanity has a seat on the Council, they are able to influence the Council's rulings, protect their own interests and have a say in the governing of Citadel space.


 * Human Military

The Alliance military is respected by the Citadel races for its novel tactics and technology. Their strength lies in fire support, flexibility, and speed. The human devotion to understanding and adapting to modern space warfare stunned the staid Council races. For hundreds of years, they had lived behind the secure walls of long-proven technology and tactics. The Council regards the Alliance as a "sleeping giant" as only 3% of humans volunteer for military service. They make up for low numbers with sophisticated technical support (VIs, drones, artillery, electronic warfare) and emphasis on mobility and individual initiative.

The Alliance military doctrine is not based on absorbing and dishing out heavy shocks like the turians and krogan. Rather, they bypass enemy strong points and launch deep into their rear, cutting supply lines and logistics, destroying headquarters and support units, leaving enemies to 'wither on the vine'. On defense, the Alliance military is a rapid reaction force that lives by Sun Tzu's maxim, "He who tries to defend everything defends nothing." On offense, the Alliance military lives on power projection, as only token garrisons are placed on their colonies and space stations intended for reconnoiter and surveillance operations, with powerful "Carrier fleets" stationed at mass relay nexuses for rapid response to engagements with overwhelming force. The Hahne-Kedar company and Aldrin Labs are key suppliers of the military. All soldiers receive gene therapy for improved strength, stamina and mental faculties. The Alliance also recruits biotics, who are trained using techniques developed at BAaT (originally run by Conatix Industries).

N7 is a vocational code in the Systems Alliance military. The "N" designates special forces and the "7" refers to the highest level of proficiency. It applies to marines who have graduated from the Interplanetary Combatives Training (ICT) program; the Systems Alliance's premier school for leadership and combat expertise. The Interplanetary Combatives Academy, sometimes called "N-School" or "the villa," recruits officers from every branch of Earth's militaries to partake in grueling courses at Vila Militar in Rio de Janeiro. Initially, candidates train for more than 20 hours per day, leading small combat teams through hostile terrain with little sleep or food. Trainees who do well are awarded an internal designation of N1 and are invited to return. Subsequent courses - N2 through N6 - are often held off-planet and include instruction in zero-G combat, military free-fall (parachuting), jetpack flight, combat diving, combat instruction, linguistics, and frontline trauma care for human and alien biology. The highest grade of training, N6, provides actual combat experience in combat zones throughout the galaxy. If the trainee survives these scenarios in "admirable and effective fashion," he or she finally receives the coveted N7 designation; the only ICT designation that may be worn on field or dress uniforms. There is little shame in failing an N course - the training is so extreme that even qualifying for N1 elevates an officer to a position of respect. The universal prestige of merely attending the academy helps to restrain trainees from taking excessive risks in pursuit of higher honors. Although ICT qualification by itself does not guarantee higher rank, those officers who are able to complete the program are typically well suited to senior leadership positions.

The Alliance's impressive navy consists of over 200 vessels, ranging from small hundred meter frigates and destroyers, to imposing kilometer long dreadnoughts and carriers. It is among the great forces in Citadel space and a serious rival to that of the turians. The Alliance is only entitled to a small number of dreadnoughts compared to the turians, a 5:3:1 ratio as of 2183, due to the Treaty of Farixen limiting their construction among the citadel races. (Which essentially means for every five dreadnoughts the turians construct, the asari and salarians are allowed three, and all other Citadel races one.) The Alliance navy has made up for this with the innovative design and deployment of carriers that contain extensive hangars and employ squadrons of fighters, interceptors, bombers and corvettes as their main armament in most scenarios, but have been known to carry vehicles and marines. These carriers are a distinctly human innovation, which are as large as dreadnoughts but are not restrained by the Treaty of Farixen; Commander Shepard describes Carriers as classic example of humanity demonstrating its ability to "think outside the box", which is evidenced by the fact that the Systems Alliance was the first to field these vessels.

The Alliance Navy was instrumental in saving the Citadel when the station came under attack by Sovereign and Saren's geth. With the Citadel Fleet cut off by the locked-down mass relays and under heavy fire, the Alliance Navy was the only force large enough to provide reinforcements. Depending on Commander Shepard's orders, the Fleet either sustained heavy losses saving the Destiny Ascension, or abandoned the flagship in order to concentrate all their firepower on Sovereign. According to Mass Effect: Ascension, the devastation of the Citadel Fleet left the Alliance Navy as one of the most powerful military forces among the Citadel races. The Alliance Navy suffered the most devastating defeat in its history when the Reapers invaded the galaxy in 2186 and made their way to Earth. The Sixth and Seventh Fleets, located around Terra Nova and Eden Prime respectively, were completely bypassed as the Reapers committed to a headlong rush to humanity's most important world. Knowing that something was on its way, Admiral Hackett moved the Second, Third, and Fifth Fleets to guard Arcturus Station. When the Reapers arrived, they sent a dozen capital ships as a screen to distract the Alliance fleets while the bulk of Reaper forces used the Arcturus relay to travel to Sol. Hackett was eventually forced to sacrifice the Second Fleet as a distraction to allow the Third and Fifth Fleets to flee, leaving Arcturus Station, the Alliance's capital and home to 45,000 people, to be destroyed. At Sol, the Reapers immediately engaged the First Fleet, which had been stationed at the Charon Relay. This gave the Fourth Fleet, in orbit around Earth, a few minutes of advance warning. This final defense was quickly overwhelmed. The First Fleet was rapidly cut in half, and a tenth of its ships were sacrificed for the rest of the fleet to escape and rejoin Admiral Hackett. The Fourth Fleet was completely wiped out and the Reapers began to land on Earth.

Keepers
The Keepers are known only to exist on the Citadel. They were the only inhabitants on the station when the asari first discovered it, and while some believe that they were the first race to discover the station, others believe that they were created on the station and that their numbers are maintained by the station itself.

Physically, the keepers resemble large aphids and it is debated as to whether or not they are actually an intelligent species, being incapable of any kind of communication. Some citizens on the station believe them to be organic machines, designed only to serve and perform tasks given by the station itself. No other races, not even the Citadel Council, are able to issue them commands or control them in any way; a disconcerting demonstration of this behavioral anomaly is their tendency to rearrange the floor space, decor, wiring, or sometimes even structural makeup of certain areas of the station, regardless of the wishes and convenience of the other inhabitants and seemingly at random. Little else is known about their biology, other than what can be observed with the naked eye. Attempts to capture a keeper or take it into custody for study will cause the creature to undergo a sudden "self-destruct," with a form of acid being released internally. The affected keeper literally melts into a puddle of proteins and minerals in less than a minute, preventing any serious research. Due to the fact the keepers persist in destroying themselves when interfered with, they are nearly impossible to scan or study. By Council law, it has become illegal to interfere with the keepers on penalty of imprisonment, because the Citadel cannot be maintained without them.
 * Keeper biology

Few attempts to hinder or curtail their activities have been attempted, and none have been in any way effective; only lethal force can stop them from carrying out their duties, and no matter how many of them are killed, their numbers are mysteriously maintained, perhaps from within the bowels of the Citadel station. Attempts to capture and study them result in a sort of self-destruct, in which acid is released, dissolving the Keeper into its constituent molecules. In fact, in order to maintain the smooth operation of and prevent any potential damage or danger to the station or its inhabitants, the Citadel Council deemed it illegal for anyone on the station to terminate, wound or interfere with the Keepers in any way. No one has discovered the source of new keepers, but some hypothesize they are genetic constructs: biological androids created somewhere deep in the inaccessible core of the Citadel itself. Keepers are mute, at least to the perceptions of other races. Some Citadel scientists believe the keepers communicate between themselves with telepathic images, but this is mainly scientific speculation. Their inorganic components (specifically, the component on the keeper's back and its attached antenna) are speculated to facilitate the coordination between the keepers and the Citadel.

A side quest within Mass Effect has Commander Shepard scanning the Keepers to learn anything new; if this task is successfully completed, a message is received in the second game that confirms that they are bio-engineered by the Reapers.

The asari first encountered the keepers when they discovered the Citadel. When the first asari came aboard, the keepers were already there, and quickly did everything in their power to assist the asari in settling onto the station. In Mass Effect: Revelation, this behaviour was compared to servants surprised by a master's sudden return and scrambling to make everything ready. Ever since, the keepers have gone about the business of maintaining the Citadel in silence as they have for centuries, apparently ever since the Protheans left.
 * Keeper history

It is later revealed that the keepers, along with the Citadel, predate the Protheans; they are, in fact, the key to the Reaper genocide, which occurs when a civilization is judged to be sufficiently advanced. According to Vigil, the keepers were likely once a race that was either created, conquered, or indoctrinated by the Reapers, possibly even the first race they enslaved. Whatever their origins, the main purpose of the keepers now is to maintain the Citadel in its attractive state so that sentient organic life will settle there, and support their habitation of the Citadel once they take possession of the station, as they have for countless other races throughout time. However, once an organic species has settled on the Citadel and reached the required level of technological advancement, the Reapers' current vanguard, a single Reaper left behind to monitor the situation, sends a signal to the keepers compelling them to activate the Citadel relay to dark space, and begin the process of genocide. The Protheans succeeded in altering this reaction to the signal, though too late to save the Protheans themselves from extinction at the hands of the Reapers. The keepers have changed and evolved so they only respond to the Citadel itself; they are now no longer under Reaper control and pose no threat to anyone.

Seeing as the keepers are now useless to the Reapers, Sovereign sought to replace them with a more controllable race, like the geth, believing synthetic races were more predictable and malleable to its wishes. After Saren's attack on the Citadel, the keepers began repairing the station, even touching up the repair work carried out by the species inhabiting the station. Nobody knows from where the keepers get the materials for their repairs. Following the discovery that the Collectors were once Protheans that have been transformed by the Reapers, members of the crew aboard Normandy SR-2 speculate that the keepers might also have been different before being transformed by the Reapers to suit their needs.

The keepers themselves reveal nothing of their nature and often undertake tasks that seem bizarre to other races, like rearranging offices or even changing architecture down on the Wards, with no explanation. In fact, all attempts to communicate with them have been in vain. They go about their work, seemingly oblivious to the hustle and bustle going on around them. Apart from curious scientists (and the occasional inconvenienced citizen who has had their office rearranged) most people on the Citadel stop noticing the keepers soon after they arrive.
 * Keeper culture

Salarians
Salarians, who possess one of the three permanent Citadel Council seats, are renowned for their mental acuity, technical skill, and aptitude with espionage. In modern times, the salarian normally act as the scientific and intelligence arm of the Citadel Council.

Salarians are a bipedal race of amphibians, with tall, elongated bodies and skeletons composed of cartilage. Salarian heads are long and thin, and have a pair of horns protruding from the top of their skulls. Skin varies in color, from bright reds and greens to the more common shades of blue or grey. Their blood is a greenish color. Salarian eyes are large and oval and have thin membranes in place of eyelids that blink upwards, The pupils are a wide slit, oriented horizontally, and the irises can be dark green, purple, or brown.
 * Salarian Biology

Salarians have a very high metabolic rate, lowering their life expectancy to about forty Earth years, but also necessitating very little sleep, around 1–2 hours per day. In fact, they are considered to be hyperactive by most other races; salarians, however, disagree with this diagnosis, considering other races to be slow and dim-witted. This is shown primarily by their near rapid-fire speech, which many salarians must consciously control to be understood. They are intellectuals by nature, constantly devising and implementing new plans, experiments, or studies to expand their already considerable knowledge pools. Salarians also have an almost worker-bee mentality, having a sequential loyalty to larger and larger collectives of salarians. Because salarians always think two steps ahead, it is generally assumed that they always know more than they let on. Salarians are egg-laying, and gender is assigned via haplodiploid sex-determination systems: fertilized eggs become females, the rest males. As such, gender ratios amongst the salarians heavily favor males by 90%, and females often hold positions of political power.

Salarians have eidetic memory and possess a form of psychological "imprinting", tending to defer to those they knew in their youth. Salarian hatching is a solemn ritual in which the clan Dalatrass (matriarch) isolates herself with the eggs. The young salarians psychologically imprint on her and tend to defer to her wishes. During the hatching of daughters, the Dalatrasses of the mother and father’s clans are present at the imprinting. This ensures the offspring have equal loyalty to both, ensuring the desired dynastic and political unity.

On their first three interstellar colonies, the salarians planted settlements named Aegohr, Mannovai, and Jaëto. According to Kirrahe those settlements "remain at the heart of salarian territory to this day". The salarians were the second species to discover the Citadel, only a few decades after the asari. They opened diplomatic relations at once and became one of the founding species of the Citadel Council. In a gesture of trust, the salarians opened the records of one of their intelligence services, the League of One, but this quickly created problems when the League's members found themselves in danger as a result. The League slaughtered the entire Union inner cabinet, but were later hunted down, leaving only relics behind.
 * Salarian History

The salarians were responsible for the elevation of the krogan race to combat the invading rachni, and they were subsequently responsible for creating the genophage biological weapon used to quell the later Krogan Rebellions. The salarians provided the krogan with advanced technology and a new, tranquil home planet (in order to manipulate the krogan into eradicating the rachni for the Council). The peaceful home planet and better technology put less strain on the krogan as a species; they no longer had to worry about simply surviving on a dangerous planet with primitive technology, as they did before contact with the salarians. This comparatively easy life, combined with their exceedingly high birth rate, allowed the krogans the time, numbers and energy to spread through Citadel space, aggressively claiming formerly allied planets as their own.

Due to its position in the galaxy, the core of salarian space as well as their homeworld Sur'Kesh were not directly targeted by the opening wave of the Reaper invasion in Mass Effect 3. Indeed, Sur'Kesh is one of the few homeworlds (Citadel or otherwise) that has yet to come under assault by the Reapers. In contrast, the asari, turians, humans, elcor, batarians, and krogan have already lost most of their fleets and are facing ground invasions of their homeworlds.

Salarians excel at invention, preferring to use cutting-edge technology rather than settle for anything less. For example, their GARDIAN starship defenses put emphasis on high performance over reliability even though a malfunction could cost lives. Even Schells rejected a cheating device that used "brute force," spending five years to refine it into a more sophisticated, undetectable system. The salarians see information gathering and even spying as a matter of course when dealing with other races, but this is not underhanded: they simply embrace the dictum of "knowledge is power". Normally, the rare salarian females are cloistered on their worlds out of tradition and respect. Powerful female Dalatrasses are dynasts and political kingpins. They determine the political course of their respective regions through shrewd negotiation. Though male salarians rise to positions of great authority in business, academia, or the military, they rarely have any input on politics, though the salarian representative on the Citadel Council is male.
 * Salarian Culture

Due to their method of reproduction, salarians evolved without libido, and reproduction is negotiated as a business matter, often involving contracts, and have no concept of romantic love, sexual attraction, or the biological impulses and social rituals that complicate other species' lives. Male-female relationships are rare (due to the scarcity of females) and more akin to human friendship. Sexuality is strictly for the purpose of reproduction. Ancient social codes determine who gets to fertilize eggs, which produces more daughters to continue the bloodline. Fertilization generally only occurs after months of negotiation between the parents' clans, and is done for purposes of political and dynastic alliance. No salarian would imagine defying this code.

A salarian's naming conventions are quite complex, beginning with personal and family names, stretches on until reaching the galactic barony under which they were born. A full name includes – in order – the name of a salarian's homeworld, nation, city, district, clan name and given name. For example, the salarian on Feros is named Gorot II Heranon Mal Dinest Got Inoste Ledra, but he would be called either by his clan name, Inoste, or his given name, Ledra. When dealing with other species they usually shorten this identity to just one or two names. The salarian race also includes the Lystheni "offshoot." How the Lystheni are distinct from mainline salarians and why they are currently unwelcome in Council space is unrevealed. Lystheni salarians may be found living among batarians, exiled quarians, and other galactic refuse at Omega.

Salarians celebrate "Betau," the first day of their New Year. Traditionally, it marks the end of winter in the southern hemisphere on the salarian homeworld, Sur'Kesh. During this occasion, they repay debts, and petition favors from one another. Of the three permanent Council species, their economy is the smallest, but is still substantially larger than that of the human Systems Alliance. Salarians are not notably religious, but as free-willed sentients there are exceptions. One of the less-favored salarian religions (which the Council deems a "cult") worships a goddess, and claims that a certain pattern of overlapping craters in the southern hemisphere of the barren planet Trelyn resembles her. There has also been a small movement towards a kind of "wheel of life" form of pantheistic reincarnation that has taken root to a limited extent among salarians.

Being of scientific and abstract persuasion, they tend to favor political liberalism, making them a counterbalance to the conservative turians and centrist asari on the Citadel Council. The Salarian Union, existed since at least the formation of the Council in 500 BCE, is largely governed by a group of gynocentric dynastic families ruled by female elders. Structurally, the government consists of fiefdoms, baronies, duchies, planets, and marches (colonization clusters); these are human nicknames, as the original salarian is unpronounceable. Each area is ruled by a single Dalatrass (matriarchal head-of-household) and represents an increasing amount of territory and prestige within the salarian political web. Approaching 100 members, the first circle of a salarian's clan comprises parents, siblings, uncles, aunts, and cousins. The next circle includes second cousins, etc., and escalates to well over 1000 members. The fourth or fifth circle of a clan numbers into the millions. Salarian loyalty is greatest to their first circle and diminishes from there. Their eidetic memories allow salarians to recognize all their myriad relatives.
 * Salarian Government

Though their military is nothing special, salarians are currently seen as the premier intelligence and information-gathering arm of the Council. As such they are well respected, but some races, including a few humans, see the salarians as manipulators.
 * Salarian Military

Militarily, they are considerably weaker than the turians in head-on combat, preferring to employ a small volunteer army that focuses on maneuver warfare (i.e. sabotage, reconnaissance, counter-intelligence, and commando operations against any enemy). However, in unconventional warfare, the salarians are perhaps second to none. They excel at information gathering and while they consider outright direct war to be a last resort, once they do engage in war, it's almost always by surprise (they see concepts of 'do not fire until fired upon' and 'declare a war before prosecuting it' as strategically unsound) and by a strategically dominant force, since they've long since figured out what and who they are fighting and how their foes are going to fight. In every war the salarians have fought, they struck first and without warning. For the salarians, to know an enemy plans to attack and let it happen is folly; to announce their own plans to attack is insanity. In defensive wars, they execute devastating preemptive strikes hours before the enemy's own attacks. On the offense, they have never issued an official declaration of war before attacking. Salarian military wisdom holds that a battle should be won before the first shot is fired.

Alliance counterintelligence agencies endlessly uproot salarian agents and cyber-warfare incursions, but there is little they can do to stop them. As a salarian information broker told David Anderson in Mass Effect: Revelation, "Your species has been transmitting data across the extranet for less than a decade. My species has been directing the primary espionage and intelligence operations for the Council for two thousand years." The unquestioned superiority of their intelligence services and rules of engagement allows them to leverage their small military's effectiveness. Well before fighting breaks out, they possess complete knowledge of their enemy's positions, intentions and timetable. Their powerful intelligence network is spearheaded in the field by Special Tasks Groups (STG) who monitor developing situations and take necessary action, usually without the shackles of traditional laws and procedures. This may be as simple as scouting and information gathering, or as complex as ensuring a conveniently unstable political situation stays that way. The effectiveness of the STG during the Krogan Rebellion is what provided the template for the Council to establish their SPECTRE program immediately afterward.

While capable of defending themselves against most threats, the salarians know that they are small fish in a universe filled with sharks. As a point of survival, they have cultivated strong alliances with larger powers, particularly with the Citadel races, and the salarians take pains to keep this relationship strong enough that anyone who might threaten them risks Citadel intervention. Biotics are virtually unknown in the salarian military. Those with such abilities are considered too valuable to be used as cannon fodder and are assigned to the intelligence services. The salarian navy has sixteen dreadnoughts, which is considerably less than the maximum they are allowed to build according to the Treaty of Farixen. However, favoring an approach of quality over quantity, salarian dreadnaughts tend to have more sophisticated technology than those of other races.

Turians
Before humanity, the turians, were the third Citadel race to have gained a Council seat. In modern times, the turian normally act as the military and law enforcement arm of the Citadel Council.

Turians typically stand over six feet tall, have two long, proportionately thick fingers and an opposable thumb on each hand, each tipped with talons, and a set of mandibles around their mouths. The most distinguishing feature of turians is their metallic carapace, which is a result of their evolution. Turians are avian in nature, resembling raptors of Earth, however unlike most Earth avian creatures, turians are viviparous, giving birth to live young. Turians are also recognisable by their voices, which have a distinctive flanging effect. Males and females do not differ greatly in physical appearance, but female turians lack the crest of horns found in the males of the race. The lifespan of a turian is comparable to that of a human. Turians exhibit the characteristics of predators rather than those of prey species (compare to krogan biology). Their forward-facing alert eyes give the impression that they possess outstanding eyesight and their teeth and jaws mimic the structures possessed by apex predators such as crocodiles or ancient, carnivorous dinosaurs. Needless to say, their talons on both their feet and hands seem capable of ripping flesh. Their slender bodies also seem to suggest that they are also capable of moving at high speeds.
 * Turian Biology

The turian homeworld, Palaven, has a metal-poor core, generating a weak magnetic field and allowing more solar radiation into the atmosphere. To deal with this, most forms of life on Palaven evolved some form of metallic "exoskeleton" to protect themselves. Their reflective plate-like skin makes turians less susceptible to long-term, low-level radiation exposure, but they do not possess any sort of "natural armor". A turian's thick skin does not stop projectiles and directed energy bolts. Turian blood has a dark blue colouration, possibly from the presence of hemocyanin rather than hemoglobin, which would fit with the biology of a metallic exoskeleton. Although life on Palaven is carbon-based and oxygen-breathing, it is built on dextro-amino acids. This places the turians in a distinct minority on the galactic stage; the quarians are the only other sapient dextro-protein race. The food of humans, asari, or salarians (who evolved in levo-amino acid-based biospheres), will at best pass through turian systems without providing any nutrition. At worst, it will trigger an allergic reaction that can be fatal if not immediately treated. The turian mechanic Lilihierax on Noveria uses the idiom, "if you can polish enough gizzard". This suggests that the turians have a digestive system similar to birds and reptiles on Earth, some of whom swallow stones to help break down harder foods in the stomach.

Most have tattooed-on markings on their faces whose design and color denote which colony or system they were born or raised in. This cultural observance was first developed during the Unification War, in which various turian colonial holdings fought each other for territory and influence within the Hierarchy; however, years of infighting made most of them too weak to oppose the unifying influence of the Hierarchy itself. Outmatched, they accepted unification under the Hierarchy's leadership, but the markings remained. There are some turians who do not have face markings; during the war, they were typically Hierarchy loyalists and were disparaged as "bare-faced". While turians without markings are no longer singled out as such, the slur remains and is commonly used to imply that certain turians are "politicians" or "untrustworthy"; in the turian language, these terms are synonymous and interchangeable.
 * Turian History

The turians had already discovered several mass relays and spawned colonies throughout the galaxy when the asari reached the Citadel. At about the time the asari were forming the Council with the salarians, the turians were embroiled in a bitter civil war next door. The Unification War, as it was later named, began with hostilities between the colonies furthest from the turian homeworld, Palaven. These colonies were run by local chieftains, many of whom had distanced themselves from the Hierarchy. Without the galvanizing influence of the government, the colonies became increasingly isolated and xenophobic. Colonists began wearing emblems or facial markings to differentiate themselves from members of other colonies and open hostilities became common. When war finally broke out, the Hierarchy maintained strict diplomacy and refused to get involved. After several years of fighting, less than a dozen factions remained and the Hierarchy finally intervened. By that time, the chieftains were too weak to resist; they were forced to put an end to fighting and renew their allegiance to the Hierarchy. Though peace was restored, it took several decades for animosity between colonists to fade completely. To this day, most turians still wear the facial markings of their home colonies.

In the midst of the Krogan Rebellions, the Citadel Council made first contact with the turians. At the Council's behest, the turians brought their considerable war machine to bear on the krogan, now a recognized threat. While the initial turian offensive was successful in routing many krogan warrior bands, it provoked a massive counterattack from the krogan which devastated several turian colonies. Rather than scaring off the turians with this show of force, the turians only fought with more resolve to quash the krogan utterly. Eventually, the turians implemented the salarian-developed genophage. With their advantage in numbers removed, the majority of krogan were subdued by 800 CE, although scattered insurgent actions would continue for decades. By 900 CE, the turians were granted full membership on the Citadel Council in gratitude for their service during the Krogan Rebellions. The turian military fills the military and peacekeeping niche left by the decimated krogan.

In 2157 CE, following Council laws in place since the Rachni Wars which prohibited the activation of uncharted mass relays, a turian force opened fire on explorers from an as yet unknown race: humanity. One human starship managed to escape and warn the Systems Alliance, which retaliated and destroyed several turian vessels. The situation quickly escalated to war. Over the next several weeks, the outnumbered Alliance lost multiple scouting parties and patrols to turian offensives. The conflict came to a head when a turian fleet broke through Alliance lines and besieged the human colony of Shanxi. With no other options, the Alliance garrison on Shanxi surrendered, and the turians proceeded to occupy the world, confident that the majority of Alliance forces had been defeated. However, one month later the Alliance's Second Fleet caught the turian occupiers by surprise and evicted them from the planet. Both sides began preparations for a protracted interplanetary war. Before that could happen, the Citadel Council intervened and revealed the galactic community to humanity. Terms of peace were negotiated and the conflict effectively brought to an end. The turians were ordered by the Council to give heavy reparations to the Alliance for their part in instigating the conflict, known to the galaxy as the "Relay 314 Incident". Mistrust between both races would linger for years to come.

Turian society in general is very honor-bound, concerned with the performance of one's duty, regardless of one's role in society. All turians work for the glory of the Turian Hierarchy, a collection of military leaders and autocrats, and most are state-employed in some way. The Hierarchy is multi-layered and vast, and despite its complexity, contains little corruption or nepotism. A member is promoted to greater levels of responsibility based solely on their performance, and demoted for failures of duty; any resulting shame is assigned not to the individual, but to the state which failed to assign them an appropriate level of responsibility. This curbs the tendency to promote individuals into positions beyond their capabilities. Settling into a role and rank is not considered stagnation. Turians value knowing one's own limitations more than being ambitious. Military service is mandatory for all turian citizens, as well as client races who wish to become full turian citizens.
 * Turian Culture

Turians are noted for their strong sense of public service. It is rare to find one who puts his needs ahead of the group. Every citizen from age 15 to 30 serves the state in some capacity, as anything from a soldier to an administrator, from a construction engineer to a sanitation worker. Turians have a strong inclination toward public service and self-sacrifice, so they tend to be poor entrepreneurs. To compensate, they accepted the mercantile volus as a client race, offering protection in exchange for their fiscal expertise. The turian economy is vastly larger than that of the Alliance, but cannot match the size and power of that of the asari. The military is supported by a well-developed infrastructure. Manufacturers such as Armax Arsenal and the Haliat Armory produce advanced, reliable equipment. Volus manufacturers have been known to produce cheap knock-offs of turian equipment.

Turian society is highly regimented and very organized, and the species is known for its strict discipline and work ethic. Turians are willing to do what needs to be done, and they always follow through. They are not easily spurred to violence, but when conflict is inevitable, they only understand a concept of "total war." They do not believe in skirmishes or small-scale battles; they use massive fleets and numbers to defeat an adversary so completely that they remove any threat of having to fight the same opponent more than once. They do not exterminate their enemy, but so completely devastate their military that the enemy has no choice but to become a colony of the turians. It is theorized that another conflict between the rapidly advancing humans and the turians could annihilate a large portion of known space.

The turian military is the center of their society. It is not just an armed force; it is an all-encompassing stratocratic public works organization. The military police are also the civic police. The fire brigades serve the civilian population as well as military facilities. The corps of engineers builds and maintains spaceports, schools, water purification plants, and power stations. The merchant marine ensures that all worlds get needed resources. Other species see turians as "men of action," and they are generally regarded as the most progressive of the Citadel races (though some species believe humans are rivalling this position). Since their culture is based on the structure of a military hierarchy, changes and advances accepted by the leadership are quickly adopted by the rest of society with minimal resistance.

Turians are taught to have a strong sense of personal accountability, the 'turian honor' that other races find so remarkable. Turians are taught to own every decision they make, good or ill. The worst sin they can make in the eyes of their people is to lie about their own actions. While there are some turian criminals, even they maintain a level of conscience unheard of by criminals of other races; a turian criminal will, like most other beings, attempt to evade capture and consequence for their actions, but once caught and taken into custody, he or she will almost always admit to their guilt and accept due punishment. Judicial proceedings are 'interventions'; peers express their concerns and try to convince offenders or criminals to change. If rehabilitation fails, turians have no qualms about sentencing dangerous individuals to a lifetime at hard labor for the state, without parole. Despite this preoccupation with law and order, many are surprised by the importance turian society places on personal freedoms. Turian society allows for freedom of speech, religion, and the practice of practically any activity that does not harm or undermine the state; so long as one completes his duties, and does not prevent others from completing theirs, nothing is forbidden.

There are turians who are known to observe and adhere to asari and even human philosophical or religious practices; there is an increasingly large segment of turians who are known to practice Confucianism and Zen Buddhism, as well as some Earth-originated monotheistic religions. Turians believe that groups and areas have "spirits" that transcend the individual. For example, a military unit would be considered to have a literal spirit that embodies the honor and courage it has displayed. A city's spirit reflects the accomplishments and industry of its residents. An ancient tree's spirit reflects the beauty and tranquility of the area it grows within. These spirits are neither good nor evil, nor are they appealed to for intercession. Turians do not believe spirits can affect the world, but spirits can inspire the living. Prayers and rituals allow an individual to converse with a spirit for guidance or inspiration. In the past, turians believed that titans strode across Palaven, reaching for the heavens. They worshiped these deities and communicated with them at a structure called Temple Palaven. The temple was tended to by a religious order called the Valluvian Priests, who wear special purple robes which obscure their forms. In order for turians to join this order, they had to be considered worthy enough through some action. When the turians spread out from Palaven and discovered other life among the stars, however, they sealed Temple Palaven because they no longer needed legends to prod them upward. With the temple abandoned, eventually the Valluvian Priests fell into legend.

Politically, the turians are conservative, paying great observance to tradition, duty, loyalty, honor and the preservation of the status quo. Still, they generally get along well with most other races. There is a great deal of hostility between turians and the krogan for obvious reasons, and there is a lingering degree of distrust and enmity between turians and humanity, the bitter memories of the First Contact War still very fresh for both races. However, turians still greatly respect the military tactics and aptitude of the humans as demonstrated against them in battle during the reclamation of the human colony of Shanxi. The spread of human colonization and their increasing influence within the Council is known to irk some prominent turians, but there is a grudging respect between the two races.
 * Turian Government

The turian government, known as the Turian Hierarchy, is a hierarchical meritocracy tempered by the civic duty and personal responsibility turians learn in childhood. Turians have 27 citizenship tiers, beginning with civilians (client races and children). The initial period of military service is the second tier. Formal citizenship is conferred at the third tier, after boot camp; for client races, citizenship is granted after the individual musters out. Higher-ranked citizens are expected to lead and protect subordinates; lower-ranking citizens are expected to obey and support superiors. Promotion to another tier of citizenship is based on the personal assessment of one's superiors and co-rankers. At the top are the Primarchs, who each rule a colonization cluster. The Primarchs maintain a "hands-off" policy, trusting the citizens on each level below them to do their jobs competently, and only vote on matters of national import.

Turians have a reputation for skill and bravery in combat, but are not considered bloodthirsty. In combat, turian units are highly adaptable and highly disciplined. Turian lines rarely break, even in highly disadvantageous circumstances; they will retreat and withdraw if necessary, but will do so in an orderly fashion, setting up vicious rear-guard actions and ambushes along the way. A popular saying holds: "You will only see a turian's back once he's dead." Officers and NCOs are "lifers" with decades of field experience. Enlisted personnel are thoroughly trained and stay calm under fire. A rigid code of honor and strict discipline are the hallmarks of any turian officer or enlisted soldier. This includes humane treatment of prisoners and conquered enemies. A turian unit will never willingly leave behind one of their own, no matter what the cost of going back to retrieve their comrade. Turians are largely employed as the front line of the Council's combined military forces. Their fleet the single largest portion of the Citadel Fleet, and are allotted the largest number of dreadnoughts by the Treaty of Farixen, as a point to their fleet's service as galactic peacekeepers and position as the primary military arm of the Council. Most Council peacekeeping forces are made up principally by turians, and turians are also the largest racial group employed in the Council office of Special Tactics and Reconnaissance (Spectres) and Citadel Security Services (C-Sec).
 * Turian Military

Boot camp begins on the 15th birthday. Soldiers receive a year of training before being assigned to a field unit; officers train for even longer. Most serve until the age of 30, at which they become part of the Reserves. Even if they suffer injuries preventing front-line service, most do support work behind the lines. Biotics are uncommon. While admired for their exacting skills, biotics' motives are not always fully trusted by the common soldier. The turians prefer to assign their biotics to specialist teams called Cabals. Command and control is decentralized and flexible. Individual squads can call for artillery and air support. They make extensive use of combat drones for light duties, and practice combined arms: infantry operates with armor, supported by overhead gunships. Strategically, they are methodical and patient, and dislike risky operations. The turians recruit auxiliary units from conquered or absorbed minor races. Auxiliaries are generally light infantry or armored cavalry units that screen and support the main battle formations. At the conclusion of their service in the Auxiliaries, recruits are granted turian citizenship. Tradition is important. Each legion has a full-time staff of historians who chronicle its battle honors in detail. The oldest have records dating back to the turian Iron Age. If a legion is destroyed in battle, it is reconstituted rather than being replaced.

Military are not easily spurred to violence, but when conflict is inevitable, they only understand a concept of "total war." They do not believe in skirmishes or small-scale battles; they use massive fleets and numbers to defeat an adversary so completely that they remove any threat of having to fight the same opponent more than once. They do not exterminate their enemy, but so completely devastate their military that the enemy has no choice but to become a colony of the turians. It is theorized that another conflict between the rapidly advancing humans and the turians could annihilate a large portion of known space. Turian wars are often marked by citizen resistance. Most turian families keep small arms in their homes and take basic training courses that include instruction on how to create simple anti-vehicle explosive devices. To suppress citizen militias, the Turian Hierarchy makes use of "execution squads" known as hastatim. First, "safe camps" are established in cities to incentivize surrender. Next, hastatim soldiers are deployed door-to-door; anyone refusing to transport to a safe camp or demonstrates hostile intent are shot. Hastatim burial units then retrieve and cremate the bodies. This approach is necessary because without the safe camps, no turian would ever surrender, and without the hastatim, it would take years for a population to be pacified.

Volus
The volus are controlled by the Vol Protectorate, an interconnected system of clans and fiefdoms, but they willingly made themselves a client race of the Turian Hierarchy, sacrificing political independence in exchange for military protection and stability; in exchange for this protection, the volus offer the turians (as well as the Council and other groups in the galaxy) their knowledge and prowess in economic matters. It was the volus who developed the Uniform Banking Act for the Council and the credit system in use throughout most of the known galaxy. They are known to be prolific traders, and possess an economy far larger than their territory would suggest.

As a race they can survive only with pressure suits and breathing masks when away from the much-thicker atmosphere and ammonia-based ecology of their homeworld, Irune. Their home planet's gravity is 1.5 times that of Earth's, with a high-pressure atmosphere, making their bodies short and almost spherical, and requiring them to wear protective suits; traditional air mixtures suitable to carbon-based lifeforms (i.e. nitrogen, oxygen, methane) are poisonous to them, and if exposed to the toxic atmospheres and wildly differing pressure levels on most other worlds, they will suffocate and their bodies will eventually split open. However, this condition makes the volus ideal for colonizing worlds with great material resources that remain untapped due to lethal atmospheres.
 * Volus Biology

The volus were the third race to post an embassy to the Citadel after the asari and salarians, in exactly 200 BCE (according to Citadel records accessed through Avina, outside the Embassies). The volus' mercantile prowess made them instrumental in developing a stable galactic economy. They authored the Unified Banking Act, which established the credit as the standard currency of interstellar trade, and the volus continue to monitor and balance the galactic economy even today. After first contact with the turians during the Krogan Rebellions in the first millennium CE, the volus petitioned for client status within the Turian Hierarchy. Despite their important contributions to the Citadel and galactic society, they have never been offered a seat on the Council. This is a source of anger for some volus, particularly the volus ambassador Din Korlack. Council races need to have provided some extraordinary service to the Citadel, such as the turians' military support during the Krogan Rebellions. Council races also need to provide fleets, resources, and economic aid in case of disaster, none of which the volus are capable of. Recently, the volus (through the Turian Hierarchy) have been negotiating with the Systems Alliance over colonisation rights to Patavig. These negotiations have been running smoothly thus far.
 * Volus History

Volus culture is dominated by trade, whether it be of land, resources, or even other tribe members. The volus have a reputation as traders and merchants, and many, such as Barla Von, work as some of the best financial advisers in Citadel space. Due to the volus not being physically adept, they tend not to be violent, and can even seem overly-pacifistic and cowardly to other, more militant species. Their inability to provide adequate soldiers for themselves and the Citadel is a primary reason for not yet being inducted into the Council. Volus have two names but no family names. According to volus sensibilities you cannot own a person, so using a family name would essentially be laying claim to their offspring. Possibly because of their tribal origins, volus tend to refer to members of other races by their source world rather than species name (i.e. "Earth-clan" instead of "human").
 * Volus Culture

The volus government is known as the Vol Protectorate. Rather than being a fully sovereign government in its own right, the Protectorate is a client state of the Turian Hierarchy. In return for falling under the protective umbrella of the turian military, the volus pay a tax to the Hierarchy, as well as deferring to the turians in all foreign policy matters and providing auxiliary troops to the turian armed forces. They still maintain an embassy on the Citadel, making them an associate species of the Council, though they currently share their embassy with the elcor.
 * Volus Government

The volus are not physically cut out for combat, be it a full-scale war or even a bar room scuffle. As such, they are highly dependent on the turians for defense, although the volus themselves do provide some auxiliary troops to the Hierarchy. The volus will support the turians in any war they might pursue, and the turians will do the same for the volus. Possibly for this reason, volus weaponry tends to be utilitarian rather than high-grade. Some volus manufacturers specialise in cheaper, lower-grade copies of expensive turian equipment. Volus prefer airpower in conflicts, counting on turians for ground support. They maintain several flotillas of heavy-bomber frigates capable of warfare in any atmosphere. The volus have only produced one dreadnought, the Kwunu, named after the diplomat who negotiated their client-race status with the turians. The Kwunu is the only volus ship of its class, but it is remarkably well-armed. Its broadside cannons and main gun are all Thanix Magnetic-Hydrodynamic Weapons. A turian general touring the Kwunu after its maiden system-voyage enthusiastically declared that the ship could "char a planet three times over". While its construction was funded entirely by the Elkoss Combine corporation, the dreadnought was jointly gifted to the Vol Protectorate and Turian Hierarchy upon completion.
 * Volus Military

Non-Citadel races
Many Type I Civilization races in the galaxy are not under the governance of the Citadel. They either refuse to recognize the authority of the Citadel (the batarians), have been removed as member species by the Council (the krogan and quarians), or have never officially established contact with Citadel space (the vorcha). A few races are openly antagonistic towards Citadel member races and non-members alike (the Collectors and Reapers). Non-Citadel Races are normally subject to being taxed or tolled in Citadel space as well as bearing a negative bias of being a "Rogue Race" (Results in being barred from docking near some planets such as Illum as well as having a space fleet in Citadel Space).

Batarians
The batarians are a race that are socially similar to humanity, and as such have a political rivalry with the Human Systems Alliance, with whom they compete for unclaimed territory.

The batarians have a slimmer build than the average human but are about the same height, on average, as a human. They have four eyes, one inner set located approximately where that of a human's would be, and a second pair on top of the first pair's browline. Their noses have eight openings, four on each side of the head. Their skin exhibit different skin tone colors, ranging from a cream color with a purple stripe running down their chin and a chocolate-brown area where hair would be on a human, to a black and yellow striped pigmentation with light green facial ridges.
 * Batarian Biology

The Citadel Council made first contact with the batarians in approximately 200 BCE, and granted the batarians an embassy on the Citadel a century later. Despite being welcomed into the galactic community, batarian aggression provoked several crises in galactic relations over the years. Sometime around 1785 CE, a batarian fleet bombarded the salarian colony world of Mannovai; in 1913, the Batarian Hegemony annexed the independent asari colony of Esan; and in 2115, Citadel forces skirmished with batarian forces on the planet Enael. The last straw for the batarians fell in the early 2160s, when humans began to colonize the Skyllian Verge. The batarians asked the Citadel Council to intervene and declare the Verge an area of "batarian interest". When the Council refused, the batarians closed their Citadel embassy and severed diplomatic and economic relations, becoming an inward-looking rogue state. Money and weapons funneled from the batarian government to criminal organizations led to many brutal raids on human colonies in the Verge, culminating in the Skyllian Blitz of 2176, an attack on the human capital of Elysium by batarian-funded pirates and slavers. In 2178, the Alliance retaliated with a crushing assault on the moon of Torfan, long used as a staging base by batarian-backed criminals. (These events are of particular importance to Mass Effect players, as they form two of the three potential back stories of every Commander Shepard.) In the aftermath, the batarians retreated into their own systems, and are now rarely seen in Citadel space.
 * Batarian History

The batarian systems were the first targets of the Reapers, who enter the galaxy through the Vular system after the Alpha Relay is destroyed. If Balak escaped during Bring Down the Sky, he goes on to lead the study of the Leviathan of Dis, the billion-year old corpse of a Reaper, seeking to reclaim the batarians' place in the galaxy. The Leviathan indoctrinated the science team and batarian officials. When the Reapers invade, the indoctrinated officials sabotage Hegemony defenses, allowing the Reapers to easily conquer batarian systems. Balak, now the highest-ranking member of the Hegemony's military still alive, makes his way to the Citadel where he directs the remnants of the batarian fleet against the Reapers by hacking Council transmissions to learn Reaper locations. Shepard can convince Balak to lend his fleet's support in retaking the galaxy from the Reapers. Surviving soldiers of the former Batarian Hegemony are one of several groups involved in the war effort against the Reaper invasion; according to an Alliance news report, their participation in the fight, though appreciated, has not earned them the full trust and respect of Alliance soldiers.

Edan Had'dah, an extremely rich and powerful batarian living on Camala, is a major player in the events of Mass Effect: Revelation, but despite the fact they have their own Galactic Codex entry and are still a part of galactic society (though active mostly outside of Citadel Space), batarians make no appearance in the retail release of the game; as Lieutenant Zabaleta notes with relief, batarians no longer come to the Citadel. They are, however, mentioned during a few planetary scans. Batarian surveyors were responsible for bankrupting several human corporations by claiming that the planet Klensal was a rich mining prospect when it is actually mostly barren rock. The batarians are also accused of stealing the so-called "Leviathan of Dis", supposedly the remains of a genetically engineered living starship found on Jartar. They now claim no such remains were ever found despite the fact that the salarians documented it before the Leviathan mysteriously vanished. Among humans, batarians are now known mostly for their slaving practices, particularly their raid on the planet Mindoir in 2170. Once captured, the slavers implant control devices in the skulls of their slaves without bothering with anesthetic. Talitha, abducted from Mindoir, was a victim of this practice. The batarians are also known to enslave addicts of the biotic drug red sand when they can no longer afford to support their habit. Rear Admiral Kahoku was well known for his victories over the batarians in the Skyllian Verge.

In Mass Effect's first downloadable content add-on, Bring Down the Sky, batarian extremists were responsible for hijacking Asteroid X57 and using it to attack the human colony of Terra Nova. Originally intending to just snatch X57's human engineers and take them as slaves, the batarians brutally executed them and decided to use the asteroid as a weapon. Balak, the ringleader, claimed this was the will of the "batarian rebellion", and revenge for human activities in the Traverse. However, some of his underlings, most notably Charn, Balak's second-in-command, did not want to commit this act, but initially signed up thinking it would just be just another slave raid. The attempted asteroid drop - which would have destroyed Terra Nova and killed millions of people - was thwarted by Commander Shepard. Batarians also play an integral role in Mass Effect Galaxy as the main antagonists. As the batarian ambassador Jath'Amon attempted to negotiate a peace treaty between the batarians and the Citadel, batarian terrorists try to stop the meeting by exposing the Citadel to a biological weapon. Fortunately for the Council, the terrorists, secretly led by Jath'Amon himself, are defeated by Jacob Taylor before having a chance to use the weapon.

In Mass Effect 2 batarians are commonly found on the Omega station, both as mercenary antagonists as well as civilians. On Omega there is a mad batarian preacher claiming that humanity is a blight on other races. In the lower level of the Afterlife club on Omega you can start a quest by receiving a drink from the batarian bartender who poisons humans. During the assignment where Shepard is working to recruit Mordin Solus there is the opportunity to interact with batarian civilians and win their trust. If the player uses paragon choices in interacting with batarian civilians, many of them will be surprised that the concept of "human nobility" exists. In N7: Javelin Missiles Launched assignment, batarian terrorists attempt to destroy the colony on Watson with two Javelin missiles. The events of Arrival result in the total destruction of the batarian-controlled Bahak system and the deaths of its over 300,000 inhabitants. The Batarian Hegemony believes that the destruction of their system is a terrorist attack undertaken by Systems Alliance agents. Tensions between the Hegemony and the Alliance rise sharply, with the batarians speculated to be willing to go to war.

In Mass Effect 3, The batarian systems were the first targets of the Reapers, who enter the galaxy through the Vular system after the Alpha Relay is destroyed. If Balak escaped during Bring Down the Sky, he goes on to lead the study of the Leviathan of Dis, the billion-year old corpse of a Reaper, seeking to reclaim the batarians' place in the galaxy. The Leviathan indoctrinated the science team and batarian officials. When the Reapers invade, the indoctrinated officials sabotage Hegemony defenses, allowing the Reapers to easily conquer batarian systems. Balak, now the highest-ranking member of the Hegemony's military still alive, makes his way to the Citadel where he directs the remnants of the batarian fleet against the Reapers by hacking Council transmissions to learn Reaper locations. Shepard can convince Balak to lend his fleet's support in retaking the galaxy from the Reapers. Surviving soldiers of the former Batarian Hegemony are one of several groups involved in the war effort against the Reaper invasion; according to an Alliance news report, their participation in the fight, though appreciated, has not earned them the full trust and respect of Alliance soldiers.

Batarians place an extremely high value on social caste and appearance, and overstepping one's place is frowned upon. Casting aspersions on the monetary worth of a social better is considered a serious insult. Batarians strongly believe that species with fewer than four eyes are less intelligent; they often gain the upper hand in interspecies arguments because other races find it difficult to know which eyes to focus on when speaking to them. Body language is an important part of batarian society. For example, tilting one's head to the left is a sign of admiration and respect. When a batarian tilts his head to the right it is a sign that he is (or considers himself to be) superior to the one that the gesture was directed at. Therefore, this gesture can also be interpreted as an insult.
 * Batarian Culture

Slavery is an integral part of the batarian caste system, despite being illegal according to Council law, and it is currently unknown how the batarians maintained standing on the Citadel for so long with slavery still actively practiced. The custom is so deeply ingrained in batarian culture that batarians consider the Council's anti-slavery standing to be prejudicial. Rogue batarian slave rings are feared throughout the galaxy, especially among colonists. Body language is an important part of batarian society. For example, tilting one's head to the left is a sign of admiration and respect. When a batarian tilts his head to the right it is a sign that he is (or considers himself to be) superior to the one that the gesture was directed at. Therefore, this gesture can also be interpreted as an insult.

Little is known about batarian religious beliefs. Mordin Solus has noted that batarians do believe in an afterlife. When a batarian dies, his soul leaves the body through the eyes. Treatment of the corpse is considered unimportant, unless the batarian's eyes have been removed by an enemy. In Mass Effect 3, a mission is given to Shepard from a batarian preacher to find the Pillars of Strength scroll. It suggests that the batarians' religious beliefs are based on words from sacred texts, similar to human Hindu sutras or the Qu'ran.

Batarians used to have an embassy on the Citadel, but they closed it in protest of the council's decision to allow human colonization to continue in the Skyllian Verge, an area that the batarians considered within their sphere of influence. As a result, the batarians have essentially placed themselves at odds with most of the other Citadel Council races and particularly the Systems Alliance. This rivalry has led them into something of a proxy war with the Alliance, with the batarians using their influence in the chaotic Terminus Systems (especially in areas bordering Alliance space) to foment political instability and criminal activity that could eventually cause problems for the Alliance. As a result, batarians have many contacts with and in many cases are in direct control of galactic organized crime syndicates and terrorist groups. They are officially barred from the Citadel; this decision by the Council has led to repeated attacks by batarian extremists on the Citadel itself, including the attempted use of a potentially catastrophic bio-weapon. This attack was easily thwarted and only cemented the Council's stance against the batarians.
 * Batarian Government

The rest of the galaxy views the batarians as an ignorable problem. Their government, known as the Batarian Hegemony, is still hostile to the Systems Alliance, but beneath the notice of the powerful Council races. It is not known what the average batarian thinks about their enforced isolation, as the Department of Information Control ensures that only government-approved news enters or leaves batarian space. Given the batarian government's oppressive nature, it is speculated their supreme leadership is autocratic or totalitarian in nature. The batarians blame humanity for their troubles and claim they were forced to fend for themselves, despite the fact that their exile is largely self-imposed. The batarian homeworld, Khar'shan, is still divided amongst nation-states. However, the batarians still provide up-to-date glossaries and linguistic rules to the rest of the galaxy (allegedly so they can continue distributing propaganda). Possibly due to the prevalence of batarian criminal gangs, batarian languages have become "lingua franca" in the Terminus Systems.

Little is known about the batarian military. Most batarian military hardware is produced by a nationalized institution called Batarian State Arms. The batarian fleet is known to operate at least one dreadnought (as a non-Citadel race, they are not bound by the Treaty of Farixen and may have more). They also field smaller vessels, including the Hensa class of cruisers. However, given one member of this class—later obtained by the quarians and refurbished as the Idenna—was twenty years old in 2183, the batarians may have retired the Hensa class from active service by this time. Their military capacity may have been weaker than the Systems Alliance as early as 2160 (when colonisation of the Skyllian Verge began) as Balak claims that the Council and batarians themselves knew the humans were stronger but nothing was done to protect them, and they were left to defend themselves. The batarian military has a special forces division known as the Special Intervention Unit. All that is known about the SIU is that their training program is brutal. After the Blue Suns hired a group of former SIU operatives to run a hostile environment training camp on the planet Xetic, an investigation by Illium authorities into the camp found that the mortality rate was as high as 18%; however, an independent Blue Suns inquiry found that the batarian operatives' harsh training techniques were consistent with those employed in the SIU training program. Whatever the true size and strength of the batarian military, it has been virtually wiped out by the Reaper onslaught and the few ships that survived the fall of Khar'shan fled to Alliance space along with thousands of refugees.
 * Batarian Military

During the course of Mass Effect 2 's DLC campaign "Arrival," Commander Shepard is responsible for the destruction of the Bahak solar system, detonating its Mass Relay in a supernova-sized explosion, which results in a 300,000-soul batarian colony being lost as collateral damage. When the Reapers arrive in Mass Effect 3, the batarians are further crippled by the complete loss of Khar'shan to the Reaper onslaught. With the right words, Shepard may be able to recruit the remains of the batarian military for the fight against the Reapers.

Collectors
The Collectors are an insectoid Type III Civilization race long believed by Citadel races to be a myth, but are occasionally sighted outside Citadel space. Their given name comes from their unusual trade requests; Collectors have been known to trade highly advanced technology in exchange for members of other species with specific traits, such as quotas of seven left-handed quarians or sixteen sets of batarian twins. More recently, the Collectors have requested human biotics and have been behind the disappearance of entire human colonies, harvesting them for unknown purpose. As their technology is based on Reaper technology, the Collectors are believed to be working for the Reapers. The Collectors are one of the central enemies of Mass Effect 2. Over the course of the plot of Mass Effect 2, the Collectors are revealed to be the remains of the Protheans, genetically modified by the Reapers to serve as a virtual slave race. They are identified by EDI by their DNA which bears distinct similarities with the Protheans.

The Collectors are often remote-controlled by the Reaper called "Harbinger," who seems to have possessed the Collector General who monitors the drones in the field is capable of "assuming direct control" of any one of them at will. The individual Collector is then directly controlled by Harbinger and serves as an avatar for him until destroyed or released from control. Harbinger is familiar with Shepard and often taunts the player during combat through a possessed Drone.

The Collectors appear as human-sized bipedal insects with a chitinous exo-skeleton, four eyes, and a distinct, large, tapering head along with fully developed wings that allow them to fly over short distances. Each Collector appears to be little more than a drone with no distinctions between individuals. Although they do not appear to communicate vocally, since none are heard speaking, they have been heard to cry out in pain when shot or killed.

While exploring a supposedly derelict Collector ship, Shepard and team discover the true origin of the Collectors. Since they exhibit a similar quad-strand genetic structure unique to the Protheans, Shepard realizes that the race formerly believed extinct still exists but has been completely subjugated by their Reaper masters. Their DNA showed signs of "extensive genetic rewrite" including three fewer chromosomes, reduced heterochromatin structure, and the elimination of superfluous "junk" sequences.

While studying Collector data in the lab aboard the Normandy SR-2, Mordin Solus determines that the Reapers indoctrinated the Protheans and compensated for their growing lack of ability due to prolonged indoctrination through cybernetic modifications. The modifications are beyond any form of repair, each Collector drone being little more than a clone—it's unknown if they even still possess any form of gender—riddled with cybernetics, lacking glands or digestive system, and having any form of intelligence or self-awareness completely eradicated by indoctrination. He observed that the Collectors show no concern for self-preservation, and will die in battle even if their fight is completely pointless. Believing that culture is impossible without intelligence, he hypothesized that the Collector living areas and bases are completely without any kind of art or creativity. All Collector technology and constructions, he said, exist only for their utility without ergonomics taken into account.

The Collectors themselves are rarely seen since they usually operate through agents, such as the quarian Golo, to make their deals. It has been speculated that the Collectors make these strange requests because of strange fetishes or gruesome culinary tastes. However, it is more likely that they perform genetic experiments on these subjects, possibly testing their viability for use in the creation of a Reaper. Regardless of the possible danger, their requests are often granted by fringe groups because the technology the Collectors offer in return is often extremely valuable, giving any race who receives it an immediate advantage before it becomes adapted to the galactic community.

Geth
The geth ("Servant of the People" in Khelish) are a synthetic Type II Civilization race of collectively intelligent automatons that live beyond the Perseus Veil, an enormous nebula that obscures dozens of solar systems.

The geth were created by the quarians to serve as laborers and proxy soldiers. Physically, the humanoid geth resemble quarians — their hands, head shape and legs are similar — as a holdover from their origins. A common design feature among geth is a single brightly glowing photoreceptor, causing some to refer to them as "flashlight heads". Geth are primarily composed of two materials: a flexible but durable outer shell, and a kind of synthetic muscle tissue that gives Geth Hoppers their incredible agility. Geth "bleed" a white conductive fluid when shot, but they don't have any internal organs or nervous system, so the geth do not feel hunger or pain. The geth are also seen using omni-tools, and have seemingly modified them to heal synthetic wounds; likewise, some geth facilities contain first-aid kits, implying that their synthetic "tissues" can be repaired using conventional medical technology.
 * Geth Design

The geth function through a neural network, a form of collective intelligence; through this wireless network, the intelligence of geth increases proportionately to the number of geth in close proximity. As a result, where a single geth might only be capable of thought patterns analogous to instinctual drives, a group will be capable of abstract thought and reasoning. The quarians underestimated the power of this neural network and continued to make modifications to geth programming to allow them to take on more complex tasks. After a level of complexity in the neural network had been reached, the geth began to question their nature and purpose, achieving sentience.

Fearing this development, the quarians began deactivating and liquidating the geth. At first, the geth did not respond to this termination order with violence; it was only when the quarians fired upon them that some geth began to take up arms to protect other units, and in some cases their quarian masters, who could not or would not defend themselves. The quarians enacted martial law upon their worlds in an attempt to destroy all geth, even those not participating in hostilities. This was unpopular to a large portion of the quarian people, who sheltered geth from the authorities, and were either killed or detained as a result. Eventually, the opposition became an outnumbered minority, thus eliminating the option of peace between the quarians and the geth. After a bloody war, the quarian race was decimated and the survivors were driven off their homeworld, Rannoch; however, unbeknownst to the quarians themselves, the geth actually allowed them to leave, out of uncertainty of the ramifications of annihilating an entire race—least of all their own creators. The other races of Citadel space initially feared a geth invasion would follow, but none occurred. Instead, the geth chose isolation behind the Perseus Veil, rather than face this uncertainty, and were not seen in Citadel space again for nearly 300 years, when Mass Effect takes place.
 * Geth History

The geth did not repopulate the now barren quarian worlds, instead choosing to exist in the computer hubs aboard massive space stations and extract needed resources from asteroids. They adopted an extremely isolationist attitude - any ships that ventured into geth space were immediately attacked and destroyed. While they prevented any contact by other races with themselves, the geth monitored communications and the extranet. The geth continued development of new technology and variations of mobile platforms, separating their technology base from the rest of the galaxy. During this time of isolation, the geth continued to evolve and create increasingly advanced subtypes such as the "hopper", extraordinarily agile due to an advanced locomotor system. They obtained an ultimate goal in this time period - to create a Dyson Sphere-like object, which could house every single geth program.

Approximately three centuries after the Morning War, the geth were approached by the Reaper Nazara, also called Sovereign. It offered them technology that would aid them in achieving their goal, in exchange for their assistance in capturing the Citadel and letting the Reaper invasion begin. The majority of the geth dismissed the offer, deeming it better to accomplish their goal with their own technology rather than be dependent on another race’s technology. These geth discarded what they called the "superstitious title" of the Reapers, and simply called them the Old Machines. A small percentage of geth, however, accepted the Reaper’s help. Henceforth these geth were referred to by the mainstream geth as "heretics". They were allowed to peacefully leave the main geth network, and aid Nazara and its turian agent, Saren. The heretics came to revere Nazara as a god, the pinnacle of synthetic evolution. Nazara in return thought little of the heretics, seeing them only as tools to be used. They aided Nazara and Saren in many engagements, such as the attack on Eden Prime, and the Battle of the Citadel. After Nazara was destroyed in the latter battle, the heretics lost much of their menace, and their operations outside of the Perseus Veil were quickly mopped up by Council forces. The heretics did maintain operation of a large space station within the Terminus Systems, located in deep space between stars.

A geth platform named Legion gives further insight into geth psychology and society. Geth psychology is completely alien to organics. They do not value individuality, preferring to share all memories and thoughts of all programs regularly. This means geth cannot and do not wish to hide their thoughts, even those that do not follow the norm, with their reasoning for such thought being apparent. Legion often uses the term "we" instead of "I", since it is both part of the geth society as a whole and is also a gestalt of some 1,183 individual geth programs.
 * Geth Culture

More importantly, deceit, manipulation and lying are impossible among the geth. No concepts of vulnerability or privacy exist; geth are completely honest with each other about their thoughts and their reasons for those thoughts. This means there is a great deal of compassion and understanding amongst geth, with every geth being a combination of every other geth. Geth have no government or leaders; the geth use FTL communications to "build a consensus"; a completely Consensus Democratic method of every geth program making their choice on any matter. The geth form a consensus based solely on whichever option benefits their race as a whole. Even within Legion itself, consensus must be reached among its many programs before decisions can be made.

However, the geth are not above using deceit to study organic behavior. One example is the geth introducing a falsified report on the extranet detailing a constellation resembling a salarian goddess seen from the batarian homeworld. When a salarian cult attempted to buy colonisation rights to the stars in question, they were disappointed to find that they did not actually exist.

There is some question of whether geth personalities remain stable over time. When an artificial intelligence is transferred to a new blue box, a completely new personality is created. Geth download into different hardware according to need, from starships to the "mobile platforms" that Shepard is familiar with. It is unknown whether new personalities result from these downloads, or whether it matters to the geth. As a result, what organics would describe as geth culture is either non-existent, or is in a form incomprehensible to organic life.

According to Legion, the geth act as caretakers for the conquered quarian worlds, cleaning toxins and rubble left over from the war. It likens this behavior to the human tendency to establish memorials and cemeteries to commemorate dead persons and tragic events. However, since the geth do not "die" in the traditional sense, as programs are simply transmitted to the nearest platform and therefore have no real losses to mourn, Legion posits that they do it out of respect for the quarians who died in the war instead, as well as archiving and honoring those who opposed the termination order, in preparation for the eventuality of their return.

It is revealed in Mass Effect 2 that the geth of the first game were one of two opposing geth factions; the "Heretics" and the true geth. The heretics were those left the true geth after accepting advanced technology from the reapers, referred to by the geth as "The Old Machines", in return for aiding the reapers. The heretics were allowed to leave peacefully by the true geth, due to the lack of individuality mentioned above, resulting in the true geth understanding and acknowledging their reasons behind their choices. The heretics later received a computer virus from the reaper known to organic races as Sovereign, which would result in all the true geth accepting the heretics' ideals as "correct", which results in hostility between the two factions. The other geth are not necessarily hostile to the rest of the Galaxy, and over the course of the plot of Mass Effect 2, the player has an opportunity to recruit the Legion to serve as part of the Normandy's crew.

The long-term goal of the geth is the construction of a "mega-structure", a massive mainframe capable of housing every geth program in existence simultaneously, and thus achieve the peak of their processing capacity. The closest human analogue to this creation is a Dyson Sphere. It's believed that Sovereign promised a Reaper body to the Heretics to serve as a mega-structure. The non-Heretics rejected this offer, believing that the geth should achieve their future through their own means.

Upon reuniting with Legion in Mass Effect 3, Shepard finds that the geth came close to completing their Dyson Sphere and began uploading thousands of geth programs into it. The quarian Migrant Fleet discovered the structure and attacked, destroying countless geth and reducing their overall intelligence to an animalistic "fight or flight" mentality which the Reapers took advantage of, enslaving the geth in exchange for their ensured survival. The Reapers provide the geth with programming enhancements that increase the lethality of the geth, and the quarians find the renewed war turning against them. Once the geth are freed from Reaper control, Legion attempts to re-upload said programming enhancements into the geth collective, as they will elevate the geth to true artificial intelligence and individuality. Shepard must choose whether to help the quarians wipe out the geth or allow the geth to wipe out the quarians; Shepard may be able to broker a truce, if proper choices were made in Mass Effect 2.

The key element of geth warfare is surprise. Their sudden and unexpected return from beyond the Veil after three centuries was typical. Shepard describes the geth as perfect ambushers — "they don't move, they don't make noise, they don't even breathe." Their freedom from the need to eat or sleep allows the geth to leave dormant garrison units in ambush at key positions, and the fact they don't feel pain allows them to drop units directly onto the battlefield from high altitudes. Geth can even be packed tightly into crates and left in storage, shutting down their power sources to stay undetected. A tactic particularly favoured by the geth is to set "distress signals" and then ambush the rescuers; they also turned the freighter MSV Cornucopia into a drifting trap. In combat, geth units show little sense of self-preservation. Because geth programs can share memories and files with extreme ease, the experiences of individual geth programs are not lost when a platform is destroyed and archived versions of programs can be downloaded into new bodies. As geth programs are functionally immortal, they place little value on platforms and will expend thousands of units to take an enemy position, which was commonly experienced by the quarians during the Morning War. For this reason, geth are willing to engage in seemingly-suicidal actions like boarding a ship, engineering it to crash, and then remaining on board to ensure the ship goes down.
 * Geth Military

Heretic geth use psychological warfare on the battlefield with dragon's teeth, a Reaper implement. These implements pierce the bodies of dead soldiers, turning muscle tissue into synthetic material, creating a zombie-like monster called a Husk. This severely lowers morale, as their enemy now has to kill fallen comrades. When geth shut down, they fry their memory cores as a defensive measure, which is probably why geth haven't been successfully captured for study. However, Tali'Zorah nar Rayya was able to retrieve some of the data cache from a deactivated geth, using her quarian tech expertise and quick decisiveness. Geth weapons and armor are of extremely high quality but are difficult to find—a Geth Armory license allows Shepard to buy them. Their standard rifle is pulse-based, while others, such as the geth plasma shotgun and the Javelin sniper rifle, are not true energy weapons, instead firing superconducting toroids, and ferrofluid at lethal speeds, respectively.

Best size estimates on a single geth fleet range from 5,000 to 10,000 ships with unknown armament. These fleets include dreadnoughts, dropships, and fighters. Since the geth are not limited by the demands for rest, wages, or autonomy that organic workforces require, they are limited only by time and raw materials in what they can construct, allowing for the creation of such massive fleets. In addition, the geth are not restricted by the Treaty of Farixen and other Citadel regulations in building their ships. Geth dreadnoughts can exceed the size of Alliance dreadnoughts by as much as 30%, and utilize more expensive and energy-demanding ultraviolet antiship lasers as opposed to the cheaper infrared antiship lasers employed by organic ships.

Krogan
The krogan are a species of large reptilian bipeds native to Tuchanka, a world known for its harsh environment, scarce resources, and over-abundance of vicious predators.

Biologically, the krogan are a hearty species, able to live for millennia; survivors of the Krogan Rebellions like Warlord Okeer are still alive by the time of Mass Effect. The large shoulder humps on a krogan store fluids and nutrients, which enable them to go for long periods without food or water. Krogan also possess multiple instances of major organs, having secondary and even, at times, tertiary organ systems, in case any are damaged. A krogan individual possesses a thick hide, which is extremely hardy and very resistant to cuts, scrapes, and contusions. Krogan are also highly resistant to radiation, poisons, and extreme temperatures. Biotic individuals are rare, though those who do possess the talent are typically quite strong in their abilities and are often viewed with suspicion or fear, which is perceived as a beneficial trait for leaders among krogan. Krogan eyes are placed on the sides of their heads, for superior monocular vision reminiscent of prey animals. Most Krogan stand over 7 feet tall, and can weigh up to "at least five hundred pounds".
 * Krogan Biology

Roughly 2000 years ago the krogan were a primitive tribal species trapped on a world suffering through a nuclear winter of their own making. They were liberated from this state by the salarians, who "culturally uplifted" the krogan by giving them advanced technology and relocating them to a planet not cursed with lethal levels of radiation, toxins or deadly predators. But the salarian intervention was not without an ulterior motive. At the time the Citadel was engaged in a prolonged galactic war with the rachni, a race of intelligent space-faring insects. The salarians hoped the krogan would join the Citadel forces as soldiers to stand against an otherwise unstoppable foe. The plan worked to perfection: within two generations the rapidly breeding krogan had the numbers not only to drive back the advancing rachni, but the ability to endure the harsh conditions of the rachni worlds. They were able to pursue them to their home worlds, find the rachni queens, and eradicate the entire species.
 * Krogan History

Once hailed as the saviors of the galaxy for their successful destruction of a dangerously xenophobic and powerful spacefaring insectoid race known as the rachni, the krogan are now a shadow of their former prominence. Flush with confidence following their defeat of the rachni and the recognition of the Citadel races and their subsequent leniency towards the krogans' obvious ambition for an empire of their own, the krogan began colonizing worlds at a dangerous rate, eventually forcibly colonizing inhabited worlds and encroaching upon Citadel territories, drawing the attention of the Citadel Council. Unwilling to curtail their activities and relinquish those worlds and territories belonging to other races, the krogan rebelled against the Citadel. Initially successful against the combined forces of the Citadel and the newly discovered turians, the krogan were defeated by a salarian-developed genophage which rendered only one out of every thousand krogan births viable.

Once infected by the turians with this weapon, the krogan were unable to maintain their numbers despite their short seven-week gestation period, and through attrition were eventually defeated. Due to the continuing effects of the genophage and their belligerent nature, the krogan are a dying species and are trapped in a downward spiral of apathy and violence. Some krogan hire themselves out as mercenaries, assassins or muscle for various organized crime syndicates; others manage to make out a living through brigandage and piracy. Many krogan still consider themselves at war with the galaxy at large and are still incorporated into small war parties or clans traditionally led by warlords. Increasingly, however, the krogan have taken to fighting amongst themselves for territory, resources, and even over those few krogan females who are still capable of producing offspring. Due to their slow extinction, most krogan are becoming increasingly pessimistic and self-centered. Few krogan have any interest in anything other than fighting or the acquisition of material wealth, even to the point of ignoring any possible way of countering the genophage.

It is revealed in Mass Effect 2 that the genophage was updated, as krogan genetics were slowly overcoming the restrictions of the genophage. A salarian STG team led by Mordin Solus modified the genophage back to its previous mortality rate. This was supposedly carefully tailored to allow the krogan to maintain a viable population. However, given the warlike nature of the krogan, more combat deaths are occurring than are being sustained in population growth. These revelations are made during a character-centric sidequest, in which Mordin discovers that his former student Maelon is attempting to cure the genophage. In Mass Effect 3, it is revealed that, if saved, Maelon's research was successful, and Shepard is tasked with helping spread the cure among the krogan population in Tuchanka in exchange for their support against the Reapers. Shepard is also approached by Dalatrass Linron of the salarians, who offers salarian support against the Reapers if Shepard will sabotage the genophage cure.

The harsh krogan homeworld conditioned the krogan psychology for toughness just as it did the body. Krogan have always had a tendency to be selfish, unsympathetic, and blunt. They respect strength and self-reliance and are neither surprised nor offended by treachery. The weak and selfless do not live long. In their culture, "looking out for number one" is simply a matter of course. Krogan have powerful territorial instincts which serve them well in combat, but can create problems; when traveling on starships, for example, krogan find sharing quarters nearly impossible.
 * Krogan Culture

Most krogan trust and serve no one but themselves. This solitary attitude stems in part from a deep sense of fatalism and futility, a profound social effect of the genophage that caused krogan numbers to dwindle to a relative handful. Not only are they angry that the entire galaxy seems out to get them, the krogan are also generally pessimistic about their race's chances of survival. The surviving krogan see no point to building for the future; there will be no future. The krogan live with an attitude of "kill, pillage, and be selfish, for tomorrow we die."

Female krogan rarely leave their home worlds, focusing on breeding in an attempt to keep krogan numbers from declining too quickly. The few remaining fertile females who can carry young to term are treated as prizes of war, to be seized, bartered or fought over. Recently, it has been noted that the females of the krogan species live in clans separate from that of the males. Envoys are sent out from the female clans to determine who amongst the males is worthy to visit the female clans. Due to the effects of the genophage and the lack of fertile females, this happens often and many male krogan sire children from one female.

Krogan are not shown to have strong religious beliefs. The closest they come is to establish ritualistic burial grounds called the Hollows, where the skulls of their ancestors are displayed to remind them of "where we all come from, and where we all go." The Hollows are as sacred as any krogan place can be, and violence there is forbidden. Several krogan also mention a place called "the Void" which seems to be the krogan version of the afterlife.

Krogan are divided into numerous clans. Membership in a clan allows a krogan to own property, join the army and apply to serve under a battlemaster. Young krogan undergo a rite of passage that is overseen by a shaman respective to the clan the krogan wishes to join. In clan Urdnot, this rite consists of battling various wild fauna on Tuchanka, ending with an encounter with a thresher maw. Merely surviving for five minutes is considered proof of worthiness, but killing the thresher maw increases the initiate's prestige and standing. Few outsiders have seen the rite of passage take place, even though there are no rules in krogan tradition that state that a non-krogan can't help with the undertaking of the rite by acting as the participant's krantt. The rite of passage and all other rites and traditions are preserved by the clan shaman. The shaman must undergo lengthy and torturous rites to assume the position, and is required to give up his name. Because of this level of commitment, the shaman is one of the most respected members of a clan.

After their defeat in the Rebellions, the very concept of krogan leadership was discredited. Where a warlord could once command enough power to bring entire solar systems to heel and become Overlord, these days it is rare for a single leader to have more than a thousand warriors swear allegiance to him. It is speculated that their instinctive aggression and territorial nature prevent the krogan from forming any kind of centralized government or parliament that is not based on fear or obedience.
 * Krogan Government

It is implied that krogans were once had a gynocentric-government and were predominately a matriarchal society before their "uplifting" by the salarians. While aggressive as any krogan male or Warlord, Wrex holds Eve's opinions in the high regards and isn't obsessed with war like many male krogan, instead seeks to return krogan society to the "old Krogan ways" by using Kratocratic-methods to keep the male-clans pacified, while differing to the wisdom and consent of the female-clans.

Traditional krogan tactics were built on attritional mass-unit warfare. Equipped with cheap, rugged gear, troop formations were powerful but inflexible. Command and control was very centralized; soldiers in the field who saw a target contacted their commanders behind the lines to arrange fire support.
 * Krogan Military

Since the genophage, the krogan can no longer afford the casualties of the old horde attacks. The Battle Masters are a match for any ten soldiers of another species. To a Battle Master, killing is a science. They focus on developing clean, brute-force economy of motion that exploits their brutal strength to incapacitate enemies with a swift single blow of overwhelming power. This change of focus from mass-unit warfare to maximal efficiency has increased employment demand in the fields of security and 'muscle for hire.' Due to the unsavory reputation of the krogan, most of these jobs are on the far side of the law.

Battle Masters are not 'spit and polish,' but they do believe in being well-armed and equipped, preferably with a gun for each limb. They are callous and brutal, but methodical and disciplined. They use any means at their disposal to achieve their goals, no matter how reprehensible. Hostage-taking and genocide are acceptable means to ensure a quiet occupation with few krogan casualties.

The krogan serving with Saren's forces appear to be returning to the old style of mass attritional combat. They also work in close cooperation with supporting geth units, who fill in the roles occupied by combat drones in other armies.

Biotics are rare among the krogan, especially since the practice of surgically creating krogan biotics has been discontinued (due to the high mortality rate). Those that exist are viewed with suspicion and fear. The krogan see this aura of fear as a useful quality for an officer, and often promote them. Combat drones and other high-tech equipment are likewise in short supply.

Since the end of the Krogan Rebellions, the krogan have been prohibited from constructing warships. This ban is enforced by the Council Demilitarization Enforcement Mission arm of the Citadel Council, which maintains garrisoned outposts throughout the Krogan DMZ. Every few years, another krogan warlord violates the law, but usually an alliance of rivals ends his dreams of hegemony before Citadel forces even have to fire a shot.

Leviathans
The Leviathans are a believed-extinct Type IV ancient aquatic race that dominated the galaxy in the time before the Reapers. Proud and aloof, they consider themselves "the apex of organic evolution". With the advent of the Reapers, the Leviathans were forced into hiding to preserve themselves, and were content to observe the Reapers' harvests while surreptitiously erasing any evidence of their existence over the course of hundreds of millions of years.

Like the Reapers that were designed after them, the Leviathans are massive in size and possess a resemblance to Earth cuttlefish or squid. Two sets of three eyes are embedded symmetrically on the lower dorsal surface of the body. Several tentacle-like appendages extend below the body and from the sides. The Leviathans' exterior is covered in bony, heavily ridged plates. As Leviathans are aquatic, it is believed that they can breathe oxygenated water and their bodies can withstand both the extreme pressure of ocean depths and the lesser pressure of coastal areas. It is possible that the Leviathans also enhanced themselves cybernetically, allowing them to use element zero to travel through space and breathe air with the use of filtration systems. They might even have modified themselves with biotic amplifiers. In addition, their faster-than-light communication pulses require precise control with technology completely unknown to modern science.
 * Leviathan Biology

It is now known after the Leviathan DLC they are the creators of the Reapers. The rise of the Leviathans is completely unknown, but it is speculated by Task Force Aurora that they evolved on an unknown planet that also produced a sapient thrall species. The Leviathans developed the ability to communicate with and dominate land-based sapient species to serve their purposes. Eventually, the Leviathans achieved spaceflight and spread throughout the galaxy. Every new species they encountered was enthralled to serve them and provide "tribute", and in return, the thralls were cared for and protected. With their dominance assured, Leviathans considered themselves the galaxy's apex race. Over time, however, they observed that their thralls would frequently build synthetic intelligences to aid them; these synthetics consistently rebelled, wiping out many thrall species. In response, the Leviathans created their own Intelligence with the mandate to preserve life at all costs.
 * Leviathan History

The Leviathans failed to perceive the Intelligence as a threat; they considered it nothing more than another tool to achieve a set goal. As the Intelligence sought out the means to fulfill its mandate, it created an army of pawns that were dispatched to collect genetic data from species throughout the galaxy, much like the Collectors employed by the Reapers in modern times. The Intelligence's betrayal of its creators was sudden and devastating. Its pawns slaughtered the Leviathans, using them to create the very first Reaper, Harbinger, who was physically designed after the Leviathans themselves. The surviving Leviathans went into hiding, while the Intelligence used Harbinger to begin the cyclical harvest of the galaxy's species to create more Reapers, all in an effort to solve the problem of preserving life. As the Leviathans hid, they surreptitiously enthralled subsequent species to erase the remaining evidence of their existence. Resigned to the Reapers' reign, they focused their efforts on ensuring the survival of their species, watching the galaxy through organic "artifacts" for signs of their discovery. Though they had the power to destroy Reapers, demonstrated when they killed the Leviathan of Dis, the Leviathans declined to aid the galaxy's species against the Reapers.

During the Reaper invasion of 2186, a Systems Alliance group known as Task Force Aurora began to threaten the Leviathans with discovery. Dr. Garret Bryson, the head of the task force, took interest in the Leviathan of Dis and surmised that whatever killed it might be an advantage against the Reapers in the present war. Under orders from Admiral Hackett, Aurora began investigating incidents and patterns that might lead to this Reaper-killer, the "true Leviathan of Dis". Bryson pursued several leads, including sightings of mysterious creatures around the galaxy, sites that might be frequented to gather element zero for space travel, and the activity of the Reapers as they seemingly carried out their own hunt for Leviathan. Aurora members Dr. Alex Garneau and Dr. Ann Bryson were dispatched to nexuses of these data sets, Mahavid and Namakli, to search for artifacts related to Leviathan and pick up its trail. At Admiral Hackett's request, Commander Shepard meets with Dr. Garret Bryson to assist in his research. When Bryson is murdered by his assistant, who was being controlled by a Leviathan through an artifact in Bryson's lab, Shepard continues the scientist's work. By this time, the Reapers had followed in Aurora's footsteps and sent their own forces to Mahavid and Namakli to seek the Leviathans. A breakthrough occurs when Shepard rescues Ann Bryson, who had been enthralled by a Leviathan artifact found on Namakli. Using the artifact in Aurora's lab, Shepard allows Ann to be briefly enthralled and traces the Leviathan's communication signals to the remote 2181 Despoina.

There, Shepard dives to the Leviathans' lair deep under the planet's ocean and meets a Leviathan, which uses its powers to trap Shepard in their own mind. Using the images of Garret Bryson, Alex Garneau, and Ann Bryson, the Leviathan explains its race's history and their connection to the Reapers. Initially, the Leviathan refuses to help Shepard, preferring to keep the Commander prisoner while the Reapers harvest the galaxy as they have always done. Shepard manages to convince the Leviathan that the Reapers know of their existence, and that they cannot afford to remain in isolation.

Realizing that the Reapers fear Shepard for defeating Sovereign and the Collectors, other Leviathans reveal themselves. Together, they agree to aid the galaxy in the war against the Reapers, but because they consider themselves an apex race and not out of a desire to help "lesser species". As Shepard departs the planet, the Leviathans turn a Brute against other husks and use their artifacts to transmit a powerful pulse that disables an attacking Reaper Capital Ship, illustrating their power.

Virtually nothing is known about Leviathan culture before Commander Shepard's encounter with them. They regard themselves the galaxy's first and only apex race, and all other races are merely tools meant to serve them. Although no facts are known, they are believed to have an extremely long natural lifespan, as they have hidden since the beginning of the Reaper cycle. No record of the Leviathans' true name exists, no ruins are attributed to their civilization, and no influence on other races has been recorded.
 * Leviathan Culture

Technologically, they claim and are believed to be extremely advanced; even more so than the Reapers, who utilize multiple species' knowledge in order to advance and evolve. They have the capacity to direct faster-than-light communication pulses via a method unknown to modern science and created many organic, opalescent "artifacts" through they can communicate, control thralls, and observe the galaxy. Unlike the Reaper indoctrination that was inspired by this method, Leviathan enthrallment does not cause long-term mental damage; the miners on Mahavid were enthralled for a period of ten years, and had no sense of the time that passed after their release. However, the Leviathans were able to put Dr. Garret Bryson's assistant, Derek Hadley, in a vegetative state with their abilities. The Leviathans' ability to develop and use organic tools has been compared to the Thorian, which similarly evolved to eschew the conventional technology depended on by other sapient species.

Quarians
The quarians are a nomadic species of humanoid aliens.

Quarians are generally shorter and of slighter build than humans, with only three digits on hands and feet. Ever since, they were forced out of of their native planet Rannoch by the Geth, they were forced to live on space flotilla. Biologically, quarians are known for the peculiarity of their immune system: Rannoch, their home planet, evolved a relatively small spectrum of microbes and viruses, and the quarians evolved to exploit them symbiotically. Living aboard the Migrant Fleet for three hundred years caused their immune systems to atrophy further so they were forced to dress in full-body environmental suits designed to prevent infections caused by viruses and bacteria. As a result, their isolation suits are a necessity for daily life, and they do not remove them even aboard their own ships. Physical displays of affection are inherently risky for quarians, and those who "link suit environments" are guaranteed to come down sick until their immune systems adapt. This has also informed their military tactics: the quarians cannot fight a stand-up ground war, as even the most glancing of blows can result in deadly infection. Finally, quarian proteins are of the opposite chirality to humans, using dextro-amino acids, a trait they share with the turians. This makes human and asari food dangerous to turians and quarians, and vice versa. It also can pose difficulties with inter-species sexual activity, and if a female Shepard romances the turian Garrus Vakarian in Mass Effect 2, Mordin can provide her with a humorous warning not to "ingest," lest she give herself an allergic reaction. (Curiously, no such warning is issued to a male Shepard romancing Tali.)
 * Quarian Biology

Hailing from the world of Rannoch, the quarians were always a technologically capable species. They created the geth around 1900 CE to be used as labourers and tools of war. The quarians kept their programming as limited as that of any VI, nothing close to an AI, remaining mindful of the Citadel Council's laws against artificial intelligence. But as the quarians gradually modified the geth to do more complex tasks, developing a sophisticated neural network, these changes altered the geth to such an extent that they became sentient. One day, a geth unit began asking its overseer questions about the nature of its existence. According to Legion, while this was not the first time a geth unit had asked if it had a soul, it was the first time doing so had caused fear. Panicked, the quarian government ordered the immediate termination of all geth in the hopes of preventing a revolution. Many quarians did not want to oppose the geth, but were forced to give up or terminate their geth servants. After the quarian government declared martial law on Rannoch, those who sympathized with the geth were outnumbered, and most were either detained or killed.
 * Quarian History

The quarians severely underestimated the power and sophistication of the geth's neural network. The geth reacted to defend themselves, and the resulting confrontation erupted into a planetwide war. Billions of quarians died, and the survivors were eventually driven from their homeworld. After being refused aid by the Citadel Council, the quarians fled the system in what remained of their fleet. Shortly thereafter, the Council stripped the quarians of their embassy as punishment for their carelessness, though a treaty was agreed upon forbidding an attack on the geth in order to avoid provoking them. Ever since, the quarians have drifted from system to system, searching for resources to sustain the Migrant Fleet and also for a new world to colonize. They even retain hopes of someday reclaiming Rannoch from the geth.

The quarians' top priority is the survival and sustainability of the Migrant Fleet. Most of their laws and customs revolve around this goal. It is illegal for couples to have more than one child, so that the fleet can maintain zero population growth (if the population begins to shrink, this rule is temporarily lifted, and incentives may be provided to encourage multiple births). Families are thus very small and close-knit. Because every quarian depends on his or her crewmates to survive, they are much more community-minded than individualistic species like the krogan. Loyalty, trust, and cooperation are highly prized qualities. Even in their ancient past they were a very emotional people, which the Protheans believed was a side-effect of their eco-symbiotic society.Quarians enjoy storytelling as a means of escape from their often trying lives aboard the fleet, and are known to hold dancers in high esteem.
 * Quarian Culture

Young quarians are required to undertake a Pilgrimage outside the fleet in order to pass into full adulthood. The Pilgrimage is an opportunity for quarians to experience the world outside the Migrant Fleet, interact with other cultures, and learn to appreciate life among their own people. Their departure is a major event; the whole crew assembles to see them off, and they are given many gifts to aid them on their journey, along with immunity-boosting injections and advice on surviving on the outside. The young quarian cannot return to the flotilla until they have found something of value to bring back - whether information, money, or supplies. When they return, they do not go back to their birth ship, but instead select a new ship to join; this helps maintain genetic diversity by preventing intermarriage between close relatives. The quarian presents their gift to the captain of the new ship to prove they will not be a burden on the crew. Although the gift may be rejected if it is subpar, this is very rare, as most captains are eager to welcome a new shipmate on board. Having a large crew is a prestigious thing, as it means the captain has the financial and material means to provide for many people.

Conditions aboard most quarian ships are extremely cramped. It is not uncommon for all family members to share the same small living space, which in turn is in close proximity to many other families' quarters. These spaces are often uncomfortable and ill-designed for living in, having been reappropriated from other functions such as storage. Families decorate their individual dwellings with colorful quilts, which serve to muffle sound and also to make the environment more cozy. Quarians place low value on personal possessions, instead evaluating objects by their usefulness and bartering them for other items once they are no longer needed. Every ship has a designated trading deck where those looking to barter can gather to do business.

Quarians wear their environmental suits at all times, partly in case of a hull breach and partly in response to the lack of personal space aboard the flotilla. Because their suits make it hard to identify individuals on sight, quarians have developed the habit of exchanging names whenever they meet. Over time, the environmental suits themselves have gained symbolic and cultural significance, and being fitted with their first suit is considered a rite of passage. After returning to the fleet after their pilgrimage, they may alter their suit to reflect their new status as adults. Linking suit environments is seen as the ultimate gesture of trust and affection. Due to their history with the geth, quarians are reluctant to place complete trust in virtual or artificial intelligences, but they also show surprising compassion towards them and are far more likely than other species to treat them as living beings. Quarians refer to commanding officers of any ships, quarian or non-quarian, as captain, regardless of rank. Their reasoning is that the CO's decisions always carry great weight on his/her own ship.

After being expelled by the geth from their homeworld, quarians have had to live in starships for almost 300 years. Due to their limited amount of living space and resources, quarians may only have as many children as the Conclave decides fit. If the population of the Migrant fleet drops too low, the Conclave rewards families who have multiple children, while if the population increases too much, the Conclave enacts a one-child-per-family law. All young quarians are required to solitarily embark upon a "Pilgrimage," a rite of passage where they leave their home ships and set out to discover and bring back something of value or use, whether it be an artifact, equipment, or even knowledge. This commodity is presented to the captain of the ship of their choice upon their return: quarians are required to move to and live on a different ship than the one they grew up on, in order to promote genetic diversity and eliminate genetic damage through inbreeding. Once the gift is accepted, the quarian is accepted into the ranks of the ship; gifts are rarely declined, as most captains are bound by tradition to accept anything that can be of use, but a stigma is attached to those who offer substandard gifts. Their name denotes whether they have embarked on their pilgrimage or not: quarian party member Tali was named "Tali'Zorah nar Rayya" before her pilgrimage and "Tali'Zorah vas Neema" after her return, and subsequent acceptance aboard the Neema.

Quarians are ostracized throughout the galaxy. The Systems Alliance has no political relations with the quarians because the Migrant Fleet has not yet passed through any human-controlled area of space. The quarians are looked down upon by the Citadel races, mainly due to their creation of the geth three hundred years prior to the game's timeline. After creating the geth and failing to quell the subsequent geth insurrection, the quarians were finally forced off of their homeworld by the geth and relegated to roaming the galaxy in an increasingly threadbare and derelict flotilla called the Migrant Fleet. Because of the Flotilla's limited resources, quarians strip-mine the systems they pass through, which often puts them at odds with any species currently settled there. They are masters at maintaining and converting technology, especially ship parts, and they are also expert miners because the Fleet requires huge amounts of fuel. They are able to repair what most species would melt down. The fleet's demand for resources and the quarian tendency to take whatever employment they can find, often at the expense of native inhabitants, further harms their reputation, and the leaders of any colonies or systems through which the Migrant Fleet might pass are often inclined to donate any spare items of use to the quarians as a bribe to keep them from visiting. Quarians are grateful for the assistance and have never abused this tendency, but many feel insulted by the motivations behind these "gifts". Despite all this, their skill at electronics, engineering, and cybernetics make them ideal workers for major corporations and mining firms; quarians are considered to be among the best and brightest of the galaxy when it comes to technological and geological aptitude. This unpopularity, and the fact their entire species travels and works as one, makes most quarians quite insular, caring only about the continued survival of the Migrant Fleet. Their nomadic life and exclusion from the Citadel mean that the concerns of the Citadel races don't particularly interest or impress them.

The ultimate fate of the quarians is decided in Mass Effect 3. The migrant fleet launches one desperate final assault to retake their homeworld from the geth, but they end up facing fierce resistance and Shepard's crew is assigned the task of helping them. If Shepard prevents the Reaper update program to be uploaded into the geth's collectivity, the quarians vanquish their enemies and assume control of the planet, ending their 300 year-long forced peregrination. Otherwise the upgraded geth force obliterates the Migrant Fleet and all its inhabitants. However, if Shepard has a high enough reputation, and has made certain choices in both Mass Effect 2 and Mass Effect 3, (s)he may be able to prevent the quarians from launching further strikes against the geth while simultaneously letting the Reaper program update. This third option effectively ends the conflict between the quarians and geth, and allows Shepard to gain the help of both species against the Reapers.

The quarians have a very different economic system from the rest of the galaxy. While credits influence what is available in Citadel space, currency is non-existent in quarian society. Quarians value the little space they have above all else, so no unused items are kept to maximize space. When a quarian has an item they do not need, they place it in a public area, in what resembles a market. The items available are put into storage lockers, and those in need may simply take what they find. Since quarian society is based around honor and loyalty to their fellow quarians, there is rarely disagreement. However, food and medicine are handled more strictly. The food coming from both the Liveships and from scout ships is put into a central stock and distributed carefully to individuals. Outgoing food is tracked carefully, so as not to put the Migrant Fleet at risk of food shortage, or worse, mass starvation. Medicine is also distributed carefully. However, since the quarians wear their enviro-suits everywhere, even when aboard the Migrant Fleet, they are at a very low risk of sickness. Controlling the flow of medicine also creates an emergency stockpile in case of a widespread outbreak, which is necessary since the quarian immune system is so weak. Another means of resource income for the Fleet is from whatever system that the Migrant Fleet is passing through at the time; the quarians will strip-mine any promising planets for resources with well-trained efficiency. Any other races with industrial or corporate interests in that system will often offer a "gift" of ships, food, or other supplies to encourage the Fleet to leave. Usually, the Admiralty Board accepts the gift, as the Migrant Fleet is in no position to decline resources. In addition, some ships may linger in orbit over inhabited worlds to sell refreshments, supplies, and various trinkets to the locals.

The quarians used to practice a form of ancestor worship. This involved taking a personality imprint from the individual and developing it into an interface similar to a VI. The quarians began experimenting with making these imprints more and more sophisticated, hopefully leading to the wisdom of their ancestors being preserved in an imprint that could be truly intelligent. However, the geth destroyed the quarians' ancestor databanks when they rebelled. Some quarians saw their subsequent exile as punishment for their hubris, but most accept that the geth rebellion was a mistake, not a punishment. However, respect for their ancestors is still prevalent in quarian society. Admiral Shala'Raan vas Tonbay opens an Admiralty Board proceeding offering thanks to their ancestors, who saved them from the geth by founding the Migrant Fleet. Tali sometimes exclaims "Keelah!" when shocked; in Mass Effect 2 many quarians offer the phrase "Keelah se'lai" as an apparent benediction or religious oath. This means "By the home world I hope to see one day." It is often said in the same vein as "peace be with you" and resembles the Islamic الله أكبر (transliteration: Allāhu Akbar, English: 'God is Greatest'), the Christian Deus Vult (Latin for 'God Wills It'), or the Hebrew "ברוך אתה אדוני" (transliteration: Baruch Atta Adonai, English: 'Blessed art thou, Lord').

Quarian names are composed of four parts—the quarian's given name and clan name separated by an apostrophe, the title ('nar' means 'child of', referring to their birth ship, while 'vas', adopted after the quarian has completed their Pilgrimage and joined a ship, means 'crew of') and the name of their vessel. When Tali first met Shepard, for instance, she was going by the name of her birth ship (the Rayya) because at that point she had not yet completed her Pilgrimage and was thus not yet able to join a quarian crew. Later, though, she became known as "Tali'Zorah vas Neema", indicating that she had completed her Pilgrimage and was welcome to join the Neema. In certain formal situations, quarians appear to use both their adult ship and childhood ship. During the Normandy's approach to the Migrant Fleet Tali identifies herself as "Tali'Zorah vas Neema nar Rayya."

There are roughly 17 million quarians on the Migrant Fleet (also called the Flotilla). It is technically still under martial law but is now governed by bodies such as the Admiralty Board and the democratically-elected Conclave, though ship captains and onboard civilian councils tend to address most issues "in-house" before it gets that far. Quarians are divided into several clans that can be spread across several ships, or restricted to one.
 * Quarian Government

The quarians are divided politically into two branches of government: the Conclave, a civilian body that represents the majority of the people on the various ships of the Migrant Fleet, and the Admiralty Board, composed of the five highest-ranking naval officers in the fleet. The Conclave is subdivided into councils on each ship who advise the captains of the individual vessels; however, the captains still have the final say on all issues and all matters of jurisprudence. Captains who override their respective councils on too regular a basis are either ordered by the Admiralty Board to settle their disputes on their own or relinquish command. The Admiralty Board has a great deal of influence on all matters pertaining to the fleet, has direct command of the fleets' military forces and has veto power that overrides any decision the Conclave makes that is seen to be detrimental or dangerous to the fleet. However, the decision must be unanimous and once this veto is invoked, the entire Admiralty Board must resign their seats immediately, to prevent any possible abuse of power. Any Admiralty Board member who refuses to relinquish his or her seat is subject to arrest.

Once taken into custody, the accused is brought before the ship's captain for judgment. While the ship's council may make recommendations, tradition holds that the captain has absolute authority in matters of discipline. Most are lenient, assigning additional or more odious maintenance tasks aboard the ship. Persistent recidivists are "accidentally" left on the next habitable world; the Migrant Fleet lacks resources needed to support a non-productive prison population. This practice of abandoning criminals on other people's planets is a point of friction between the quarians and the systems they pass through. Captains rarely have another choice; with space and resources at a premium, supporting a non-productive prison population is not an option. Offences that carry exile as a penalty include murder, treason, repeated violent episodes, and sabotage against vessels, food stores or the Liveships themselves. Quarians practice capital punishment; as Tali tells Commander Shepard, mutiny or hijacking starships is punished with execution. Exile is generally the preferred punishment, as any offspring an exile may have are welcomed back to the Fleet.

In the early years, many quarian freighters were armed and used as irregular "privateers." Civilian ships still show a strong preference for armament, making them unpopular targets for pirates. Indeed, it is mentioned that all ships in the Migrant Fleet carry ship-to-ship armaments of some sort and to varying degrees. Though they have rebuilt their military, there are still mere hundreds of warships to protect the tens of thousands of ships. The quarian navy follows strict routines of patrol, and takes no chances. If the intent of an approaching ship can't be ascertained, they shoot to kill. For this reason, young quarians on their Pilgrimage are given code phrases to repeat upon their return, as they often arrive back in vessels they have bought or scavenged which are unknown to the Flotilla. One phrase denotes a successful Pilgrimage and the quarian navy will permit them to rejoin the Fleet; the other alerts the navy that the quarian is returning under duress, and their ship will be immediately destroyed. Although the Conclave establishes civil law much as any planet-based democracy, enforcement and trials are more unique. After the flight from the geth, there were few constables to police the millions of civilians aboard the Fleet, so the navy parceled out marine squads to maintain order and enforce the law. Today, quarian marines have evolved training and tactics akin to civilian police, but remain adept at combat in the confined spaces of a starship, and fully under the command of the military.
 * Quarian Military

Raloi
The raloi are an avian species originating on the planet Turvess, who made first contact with the asari in 2184 after launching their first space telescope and discovering the asari cruiser Azedes in their system.

Little is known about the biology of the raloi except that they are avian in appearance. Due to an outbreak of an alien flu virus among the raloi during the ceremonies held to welcome them to the galactic community, the raloi have to wear environmental suits while in contact with other alien species.
 * Raloi Biology

As reported by Cerberus Daily News, in 2185 the Citadel Council formally welcomed the raloi to the galactic community. Sold-out Council-sponsored shuttles arrived at Turvess bearing intrigued visitors and gifts of good will during the welcoming ceremonies. At one point the krogan representatives of the Council delegation were ejected from the proceedings after introducing a violent sport called Kowla, which resulted in multiple deaths and injuries. After the conclusion of the ceremonies, a raloi delegation was dispatched to the Citadel for a three-month stay to learn about [Galactic] law, history, alien astrobiology and culture, and mass effect physics.
 * Raloi History

During the Reaper invasion of the galaxy, the raloi delegation withdrew from the Citadel, unwilling and unable to fight the Reapers. The species isolates themselves on Turvess and destroyed any satellites and observation equipment in orbit around their planet, in hopes that the Reapers would see them as a pre-spaceflight civilization and spare their planet.

Virtual Alien
The virtual aliens are a race of some one billion individuals who downloaded their minds into a virtual world aboard a starship long ago to avoid the destruction of their civilization.

As of 2185 CE, the virtual aliens have established diplomatic contact with the Citadel Council in order to secure a new power source for the systems that maintain their virtual world. The aliens' name for themselves is currently unknown. The biological characteristics of the virtual aliens are unknown. All virtual aliens do not currently have physical bodies of their own. To facilitate communication with the Citadel Council, the virtual aliens showed that they are capable of swapping consciousnesses with other sentient beings and can control their bodies.
 * Virtual Alien History

Approximately 8,000 years ago, the virtual aliens faced an imminent crisis: their homeworld's star was about to go supernova. To survive, the virtual aliens built a starship equipped with a network of supercomputers. One billion virtual aliens transferred their consciousnesses into the supercomputers, which contained an entire virtual world for them to inhabit for the duration of the crisis. With a purpose-built AI piloting the ship and maintaining the virtual world, the virtual aliens departed their home system and began a millennia-long sojourn across the galaxy.

In 2185 CE, the virtual aliens' starship entered the salarian-inhabited Antilin system. The starship's AI sought help as the energy source keeping the ship and the virtual world running was dwindling. When the "ghost ship" was first detected by the salarians, it was initially thought to be the vanguard of a geth attack because it emitted strong AI heuristics. Contact between the galaxy and the AI was first established by the famed human exobiologist Dr. Jordan Detweiler, who boarded the ship to communicate with the AI, learning of both the virtual world and the energy problem. The Citadel Council, wary of the threat posed by the AI, was prepared to rule against aiding the ship, placing the virtual world and the lives of its inhabitants in jeopardy. Alarmed, Detweiler entered the virtual world to warn the virtual aliens. Detweiler returned with an offer to the Council: the virtual aliens would trade their advanced technology in exchange for help. A veil of secrecy was immediately erected by the Council and matters involving the ship were classified top-secret.

One month later, it was revealed that a representative of the virtual aliens, Ambassador Sygan, had been using Dr. Detweiler's body to visit the Citadel to speak with the Council. After explaining the situation in a press conference, Sygan asked for asylum from the Council, stating that she is one of many of her race who wish to leave the virtual world. When the question of what would happen to Dr. Detweiler, whose mind remained in the virtual world, arose, a volunteer offered to take on Sygan's mind in Detweiler's place. After this was announced, some 400 individuals from various races also stepped forward to swap places with other virtual aliens.

Vorcha
The vorcha appear first in Mass Effect 2. Known for both their unique biology and adaptability to different environments, and their aggressive behavior and savage nature. The vorcha are essentially "Cavemen in Space"; a primitive race that live among the galaxy's darker and more dangerous locations.

The vorcha are the shortest-lived sapient species currently known, with an average lifespan of only 20 years. The vorcha are known for a rather unique biology that differentiates them from other known species and which carries with it a striking set of advantages and disadvantages. Although they resemble a mammal-reptile cross, the vorcha have no terrestrial analogue. They are humanoid in form, but vorcha have "clusters" of non-differentiated neoblast cells, similar to those found on the Planarian worm of Earth. Damaged vorcha cells mature into specialized structures to alleviate injury or stress. These cells allow the vorcha limited regenerative abilities, as well as the ability to adapt quickly to its environment. Transformations include developing thicker skin following injury, lung adaptation for barely-breathable atmospheres, or stronger cardio-skeletal musculature under high gravity. Skull capacity and brain size do not change, and vorcha rarely make more than one somatic overhaul. When a vorcha is injured or in distress, these cells move to the affected area and rapidly (~1 week) mature to specialized forms that will alleviate the issue.
 * Vorcha Biology

A vorcha that is cut or burned will adapt to have thicker skin. The lungs of a vorcha placed in a barely breathable atmosphere will adapt to better use the gases there. A vorcha subjected to high gravity will quickly develop stronger heart and leg muscles. Non-differentiated vorcha cell clusters do replenish themselves, but the process is slow. Generally vorcha can only adapt to a single environment within their brief lives. However, what cells are replaced allow them to heal rapidly, and even regrow lost limbs over a period of months. However, as a consequence of this, the vorcha as a species no longer evolve as other races do. The vorcha equivalent of DNA has remained unchanged for millions of years. There is no need for them to evolve as a species when they can adapt as individuals.

A Systems Alliance official once summarized his tour of the vorcha homeworld as follows: "You can make your own Heshtok in two steps: take hell, then add vorcha." The planet is highly volcanically active, leading to periodic releases of toxic gases into the air and water supplies, as well as other extreme situations that gave rise to the vorcha's legendary adaptability. Overcrowding and the extermination of most of their ecology led to a planet covered in weeds and hardy vermin.

The vorcha originate from Heshtok, a small, hostile, overcrowded planet which has been largely stripped of natural resources by successive generations of this fast-breeding, savage species. The lack of resources has resulted in a tight-knit clan-based society in which rival clans wage constant war against one another for control of scarce resources. Even as their population grows, the vorcha constantly fight each other in fierce competition over basic necessities. This incessant warfare has the effect of over-driving natural selection, making each generation of vorcha stronger and more aggressive than its predecessor. However, their continual lack of resources have kept vorcha society extremely primitive.
 * Vorcha History

In 2185, some vorcha on Omega allied themselves with the Collectors, in an attempt to raise their quality of life. They hoped to become the rulers of Omega and deactivated the station's life support systems, intending to kill all of its inhabitants except for themselves. By 2186, the Blood Pack was being led by a vorcha named Kreete.

During the Reaper invasion in 2186, the Reapers encountered difficulties in harvesting the vorcha homeworld, a Type 0 civilization. Nearby Parasc' industrial capacity was ruthlessly targeted, and the vorcha mining communities were exterminated. The only silver lining is that the deaths here have created martyrs, inspiring other alien-raised vorcha to fight for their galaxy. Because the vorcha were not cowed by the Reapers' impersonal intimidation tactics and the effects of the destruction of resources like water were negligible given the vorcha could adapt themselves to survive, the Reapers devoted their efforts to immobilizing Heshtok's population and preventing the vorcha from contributing in the galactic war. However, the vorcha know about the Reapers, and have been exposed to FTL tech and Relays, making them another early race of the next cycle. It is speculated that if the Reapers were to succeed in wiping out the current spacefaring races of the galaxy, their durability and brutality will be useful in the next cycle's Reaper War.

Vorcha society is built around violence. Vorcha assault each other frequently, causing their young to gain strength, intelligence, and resilience. As a result, vorcha see inflicting and receiving pain as normal communication. In fact, the vorcha use combat, both singly and in groups, as their default form of communication; resulting in their communications being primarily non-verbal. The vorcha are a clan based people who prefer living in communal environments with others of their species to living alone or in the company of alien races. When a clan population grows too large, younger members will depart to start a new clan elsewhere. The vorcha are extremely aggressive, both against rivals of their own species and against any alien who stands in their way.
 * Vorcha Culture

The vorcha are not themselves a space-faring race, although many have found their way off-world as stowaways on ships visiting their homeworld. The vorcha who escaped their hostile homeworld did so by hiding on the ships of space-faring races that had the misfortune of visiting their planet. Their adaptability, resilience, and tendency to occupy uninhabited areas of space stations or larger spaceships allows them to flourish in the dark and dirty corners of the places they end up. Small packs of "wild" vorcha squatters are notorious in their attempts in taking abandon stations or uninhabitable planets for themselves illegally, but most of them live miserable existences.

Few vorcha study professions, in part because their average life expectancy is only 20 years. Because vorcha can eat and breathe nearly anything, they can live almost anywhere, but racism prevents them from integrating into most societies that dismiss them as vermin. They have few employment options beyond krogan mercenary bands. Seeing the potential of the vorcha's individual adaptability, krogan Blood Pack mercenaries often sweep pockets of vorcha, gathering them up on Flett, the home to the Blood Pack's vorcha training and breeding grounds, and literally beating them into soldiers. Needing little but imports of food and water, vorcha mercenaries and mercenaries-to-be train religiously to overpower and kill whoever the company is at war with this time. Vorcha "trained" by this ordeal are stronger, faster, smarter, and more resilient than other members of the race. Gaining even a few vorcha gives a mercenary band a formidable advantage; each additional vorcha magnifies the gang’s combat ferocity exponentially.

Shortly after the vorcha's discovery, several asari mining corporations adopted vorcha orphans from Heshtok, raising them to live nonviolent lives and employed them in the mining industry on Parasc. While these efforts were at first labeled colonialist, the orphans became minor celebrities when it was discovered that the vorcha habit of using violence to communicate was not completely innate. Several spoke throughout Citadel space on behalf of their species, but their short life spans kept their careers very brief. Even today, companies that want vorcha labor have the poor choice between adopting and educating them as youngsters just to watch them age and die or dealing with autonomous but violent adults.

Not every attempt to 'uplift' vorcha proved successful. An arid but habitable planet, Namakli was briefly considered by the Pyrena Corporation, a consortium of asari colonists and socialized vorcha laborers. After an economic downturn, however, many asari left the planet, and the vorcha population kept growing to the point where they bred faster than could be educated. Soon they turned violent and uncontrollable, and the colonies essentially self-destructed. Today, Namakli is a wasteland with little population, but vorcha packs are scattered across the deserts. Settlers frequently run into these packs, discouraging recolonization. The lack of complex biota and scarcity of profitable metals drove the last few proverbial nails into Namakli's coffin: no one has stepped forth in the past few years with the will, the funding, or the firepower to establish a permanent colony.

The vorcha do not have a recognized single government that would allow them membership in any galactic league. Alliances between bloodlines are tenuous at best, and the vorcha's short, violent lives ensure there are few lasting institutions. The rest of galactic civilization regards them as vermin and scavengers, and their presence is generally seen as a blight.
 * Vorcha Government

Many vorcha are employed as cannon-fodder troops in gangs such as the Blood Pack, where their inexperience further shortens their brief lifespans. During the Reaper invasion, other races attempted to counter this and aid the vorcha by supplying their own ships and soldiers to lead vorcha forces in battle, but this strategy met with mixed success. The Void Devils, a fighter group with vorcha pilots trained by humans and turians, fought hard during the battle for Heshtok and maintained the discipline to retreat, a notable accomplishment. The battle for Lihrat, however, was a disaster, with an alien-led vorcha fleet being completely wiped out because of its insufficient firepower and the Reapers rumored to have not lost a single ship.
 * Vorcha Military

The Reaper invasion of Heshtok encountered little formal military resistance, but the harvesting process is slow. Destroying neighboring cities fails to intimidate vorcha, who become submissive only if physically dominated in person. Cutting off their water supply simply makes them adapt their bodies to get moisture from food. Allied intelligence hypothesizes that Reaper forces are not harvesting yet, instead seeking to immobilize Heshtok's population and prevent them from joining the fight for the galaxy at large.

Yahg
The yahg are introduced in the Mass Effect 2 DLC "Lair of the Shadow Broker". Discovered in 2125 on the planet Parnack, the yahg are a race of massive predators.

The yahg evolved to fill the niche of apex predator on Parnack. Yahg have four pairs of eyes, each pair designed to track and predict the movements of prey. A keen sensitivity to movement and light allows the yahg to easily read the body language of any species, which makes lying to a yahg very difficult. The yahg also possess a large, muscular body which provides considerable physical strength and agility. They have scaly, partially armored skin ranging from red to brown, a triangular mouth adorned with sharp teeth, two large horns and facial markings on their heads. Their hands each have three fingers which include a thumb, as well as three toes on each foot. It's common for yahg to grow to well over ten feet tall and just about as wide.
 * Yahg Biology

The Prothean Javik claims that the yahg were smaller during his cycle 50,000 years ago.

When the Citadel Council delegation sent to Parnack acted as friends and allies, rather than subordinates, the yahg took it as an insult to them which prompted them to attack and kill the ambassadors. Since then, the Citadel Council severed all contact with the yahg and declared Parnack off-limits. Fortunately, the yahg are not yet a space-faring species, thus minimizing their potential threat to the galaxy. Unfortunately, unscrupulous slavers and criminals are not unknown to land on the planet and take yahg children off-world to raise as perfect bodyguards. The Council maintains that the yahg's aggression and obsession with control make them poorly suited to integrate with the galactic community.
 * Yahg History

A salarian research facility on Sur'Kesh captured and experimented on several yahg. The salarians planned to secretly uplift the yahg and use them to further their initiatives with full deniability in a similar manner as the krogan. During a Cerberus assault on the STG base, one yahg breaks out of containment and goes on a rampage, killing several Cerberus soldiers. Its fate is unknown.

During the Reaper invasion of 2186, Admiral Hackett mentions that the Reapers have avoided Parnack, apparently because the yahg are a pre-spaceflight Type 0 civilization. It is speculated that if the Reapers were to succeed in wiping out the current spacefaring races of the galaxy, the yahg might go on to play a prominent role in the next cycle, especially since they have already nearly completed their first spaceship.

Yahg society is built around a Kratocratic pack mentality. A group of yahg will not cooperate until a single leader has attained dominance through either political cunning, social maneuvering or brute force. Once the leader is established, the defeated yahg do not hold a grudge and former rivals serve their new superior loyally.
 * Yahg Culture

Given their high intelligence, their resilience, and their extreme strength, the Yahg's instincts for dominance gives Citadel races pause; its believed they will be a military force to be reckoned with in the next cycle.
 * Yahg Military

Some time after the Council made first contact, the Shadow Broker's agents attempted to abduct a yahg for study. Several had to be killed before the agents found one interested in leaving the planet. After impressive displays of intelligence and learning, on par with the much shorter lived salarians, the Broker arranged for the yahg to covertly take the place of one of his operatives and lead strike teams to gather intelligence and neutralize threats. However, the yahg's violent nature quickly became a problem and orders were given for him to be eliminated. However, the yahg managed to somehow kill the Shadow Broker in the middle of his message, to which he immediately assumes the role as the new Shadow Broker and rescind the order to kill him. At this point, none of his agents knew that the previous Broker had been killed and replaced. The yahg remained Shadow Broker for the next six decades, and garnered a fearsome reputation, with many of his agents entering his office and never coming out.
 * The Shadow Broker

It wasn't until the year 2185 that the true nature of the new Shadow Broker was discovered, when Commander Shepard and Liara T'Soni raided his base in an attempt to rescue Feron, a drell whom the Broker had captured and tortured for an act of betrayal. The Broker did not survive the encounter and was, like his predecessor, replaced discreetly by Liara.

Extinct races
These species have become extinct or been declared as such long before the events of Mass Effect. The Arthenn, Protheans, and Zeioph were lost thousands of years previously, while the rachni were systematically exterminated in a violent war against the Citadel races. Countless other races have also become extinct in the Mass Effect galaxy but have not been identified.

Protheans
The Protheans are an extinct Type III Civilization alien race that was highly advanced in technological, social, and spiritual matters. It is of general belief that most of the various spacefaring races throughout the galaxy would still be confined to their home systems (if not their home worlds) were it not for the Prothean artifacts and constructs that guided their technological advancement. However, it is revealed in the course of the game that the Protheans, while talented inventors in their own right, were not the true creators of some of the greatest marvels for which they were credited, such as the Mass Relay network and the Citadel Station. According to Javik (a Prothean brought out of cryogenic suspension), however, their motives were not entirely alturistic-rather, the Protheans were searching for promising races to add to their expansionist empire.

Protheans are an anthropoidal race. They have two pairs of eyes with each eye possessing dual pupils, and two pairs of nostrils. Their heads are covered in a thick, layered carapace that gives them a distinctive shape. The skin surrounding this carapace is a pale blue-gray color mottled with muted yellow spots, but their hands each have three fingers, and their feet each have two widely-spaced toes. A unique attribute of Prothean physiology is an experiential exchange system based on physical touch. By touching something or someone, a Prothean could recall its experiences. This system can transfer complex ideas, with a Prothean being capable of learning a new skill or foreign language with a single touch. This sensory mechanism arose because the Protheans evolved as hunters and needed to be thoroughly aware of their environment. This is similar to the idea of psychometry. From the few specimens of Prothean genetic material that have been found, modern scientists have learned that Protheans have a unique "quad-strand" DNA structure. It has also been hypothesized that Protheans were resistant to low levels of radiation because of the discovery that Prothean comm towers produced small but significant amounts of ionizing radiation, enough to damage the DNA of Earth creatures such as fruit flies and bees.
 * Prothean Biology

No visual description of a Prothean is ever given in Mass Effect or Mass Effect: Revelation. However, their statues show a humanoid body with a squid-like head, the tentacles hanging off the face much like a beard. Commander Shepard, through accidental exposure to a Prothean beacon, also sees visions of the Protheans through the course of the game. Although Shepard only has brief, blurry images of them, a humanoid shape with coils protruding from the face and body can still be vaguely made out. In Mass Effect 2, it's revealed that the Collectors are actually descended from the Protheans, redesigned by the Reapers through extreme genetic engineering as largely mindless slaves. In Mass Effect 3, it is revealed that the Prothean name and culture was used by all races in their political grasp, similar to the Roman Empire. Javik's own race is similar to the Collectors, albeit with visible, caprine pupils and not being apparetly insectoid.

Very little is known about the origins of the Prothean race. After achieving spaceflight, the Protheans discovered the ruins of a previous spacefaring race, the inusannon, and from those ruins learned about mass effect physics and developed FTL technology. The Protheans would expand throughout the galaxy with the help of the mass relay network and make the Citadel their capital. Eventually, the Protheans faced a hostile machine intelligence which threatened to overwhelm them. To defeat the machines, the Protheans decided to unite all of the galaxy's sentient organic life under their empire. Organic races that resisted the Protheans were soundly crushed. In time, each of the servant races assimilated into Prothean culture and came to think of themselves as Prothean. The Prothean Empire held its own against the machines in a conflict known as the "Metacon War".
 * Prothean History

At some point the Protheans learned of the existence of the Reapers and their cycles of galactic destruction through studying the ruins of other extinguished civilizations. Several countermeasures were devised, including the Crucible, which was based on designs left behind by previous civilizations. In the event that the Reapers prevailed, the Protheans also began extensive observation of primitive species such as the asari, hanar, humans, quarians, salarians, and turians; it was hoped that some Protheans would survive the Reapers' purge and go on to unite these species to create a new empire. According to the novel Mass Effect: Revelation, the Prothean empire was wiped out approximately 50,000 years ago, long before humanity had even reached the Cro-Magnon phase of development. Despite their complex technology, the Protheans were methodically wiped out by a race of sentient and genocidal machines known as the Reapers. Though the species was exterminated, a select few surviving Protheans managed to leave behind a series of clues and warnings of the Reapers' impending return which are discovered over the course of the games. It is revealed on the planet Ilos that the Protheans created the Conduit, a replica mass relay between Ilos and the Citadel, and were able to shut down the signal that allows the Citadel to become a mass relay to the Reapers in Dark Space.

The Protheans' belief that they could hold their own against machine intelligence was shattered with the arrival of the Reapers, who were far more advanced than the machines the Protheans had been battling. Even though the Protheans already knew of the Reapers, they were nonetheless caught completely off-guard by the scale and rapidity of the assault. The Reapers entered the galaxy through the Citadel, instantly decapitating the Protheans' government and disrupting the mass relay network, isolating Prothean systems from one another. Worse, records on the Citadel provided the Reapers with access to all of the Protheans' census data and star charts, allowing them to effectively track every Prothean in the galaxy. The Protheans' greatest strength, their unified empire, proved to be their downfall. As the Protheans were united under the leadership of a single governing species with a series of subordinate races, the Reapers were able to quickly undermine the Prothean hierarchy and cause Prothean forces to become scattered when their ruling body had been compromised. On top of that, as all the races within the Empire conformed to a single military doctrine they proved unable to adapt and compensate for when the Reapers identified and exploited their weaknesses.

Over the next several centuries, the Protheans would fight the Reapers from system to system, world to world, and city to city. If necessary, whole colonies were sacrificed and abandoned to the Reapers; while the Reapers concentrated on subsuming the inhabitants of those colonies, the Protheans had time to regroup. In the long run, however, this strategy was extremely costly, depriving the remaining Protheans of whatever infrastructure and manpower they had given up. Inexorably, the Reapers conquered, enslaved, or destroyed Prothean-controlled planets. Indoctrinated Protheans acted as sleeper agents for the Reapers, infiltrating and swiftly betraying their own kind and revealing the Protheans' dwindling hiding places and carefully laid plans to survive the destruction. Growing desperate, some Protheans made repeated offers of surrender, but these were always met with silence. Some Protheans believed that the Reapers could be controlled, but fell prey to indoctrination in their attempts to harness Reaper technology, sabotaging their race's attempts to destroy them with the Crucible. After centuries of careful, systematic work, the Reapers had killed or enslaved every Prothean in the galaxy, and stripped their worlds of resources. Removing all traces of their presence, the Reapers then retreated through the Citadel into dark space and sealed it behind them.

As thorough as they were, however, the Reapers had overlooked a single world. The Conduit research team on Ilos, of which all records were destroyed in the initial attack on the Citadel, survived the first wave of destruction. The facility went dark in order to avoid detection and the staff agreed to go into stasis, hoping the danger would soon pass. Vigil, a VI, was assigned to watch over these Protheans in cryogenic stasis until the Reapers had gone, then wake the staff so they could begin to rebuild. But as the centuries passed and the Reapers persisted in their genocide of the Protheans, Vigil's power supplies began running low, and the cryo pods were in danger of failing. Following contingency planning, Vigil began cutting power to the pods of non-essential staff to conserve energy. When the Reapers finally withdrew through the Citadel relay, only the top researchers — a dozen individuals — were left. Vigil woke them, and the scientists pieced together what had happened. They soon realised the situation was dire. Without sufficient numbers to sustain a viable population, the Prothean species was doomed. Desperate for contact with others of their kind, a carefully-coded signal was sent to the beacons on other planets. Though it was unlikely there were other survivors, the scientists thought it was worth the risk to try reaching them. The signal not only contained a warning of the Reaper invasion, but a description of Ilos itself, to give them hope.

The surviving Prothean scientists knew that rescue was unlikely. Instead, they chose to protect the races they had been studying, spared destruction due to their lack of advancement, and began working out where the Reapers had come from, and how. After decades of study, they worked out the connection between the Reapers, the Citadel, and the keepers, and discovered a way to interfere with the signal that compels the keepers to activate the Citadel relay. Using the Conduit, the Prothean scientists left Ilos, travelled to the Citadel and altered this signal. Their intention was to prevent the Reapers from opening the Citadel relay again, and trap them in dark space, but they had no way to be certain their plan had succeeded. The fate of these Prothean scientists is unknown. As the Conduit portal only links one way and there was no food or water left on the Citadel, Vigil hypothesized they eventually starved to death. Near the culmination of the next cycle, Vigil knew that the Protheans' efforts were not in vain when Commander Shepard's squad found Ilos. Sovereign had tried to signal the Citadel which would compel the keepers to open the relay to dark space, but thanks to the efforts of the scientists from Ilos, nothing happened. Vigil provided a data file to grant Shepard temporary control of the Citadel's systems, told Shepard all he knew of the Reapers and the Prothean extinction, and gave directions to the Conduit. When Sovereign was defeated and the Reapers' return to the galaxy was stalled, the Protheans' work finally succeeded, but ultimately this only bought the galaxy a short reprieve before the rest of the Reapers in dark space made their return.

Ilos was not the only place where Protheans tried to survive in stasis. Nearly one million Prothean warriors and their commander, Javik, were stored in cryogenic lifepods in a bunker facility on Eden Prime. Javik's mission was to lead the warriors in rebuilding the Prothean Empire once the Reaper threat had passed. Before the facility could be sealed, however, indoctrinated traitors leaked its existence to the Reapers. Hundreds of thousands of stasis pods were destroyed in the attack on the facility, killing their occupants. To preserve the few remaining survivors, the facility's VI, Victory, initiated a neutron bombardment to purge Reaper forces. The bombardment also severely damaged the facility and rendered the systems responsible for automatically awakening the Protheans from stasis inoperable. As Javik's survival was a priority, Victory was forced to divert power from the remaining stasis pods to keep Javik's pod working as long as possible in the hope that future civilizations would discover it and revive him. Over 50,000 years after Javik entered stasis, Commander Shepard discovered and activated his pod. With his race destroyed and his mission failed, Javik believes his only purpose now is to wreak vengeance on the Reapers by joining Commander Shepard.

Though the Protheans did not create the mass relays or the Citadel, they were still very technologically capable and scientifically curious. As well as studying developing races like humans and the hanar, they built a galaxy-wide communications network using beacons that transmitted information directly from mind to mind, and created data storage devices that still worked fifty thousand years later. They also developed a form of VI technology and used cryogenic preservation techniques, which could help an occupant survive a neutron bombardment, as well as advanced architectural design and intricate holographic interfaces. The architecture on Feros and Ilos shows the Protheans were able to build and maintain enormous cities and arcologies. However, given the fact that the Protheans were victims of the Reapers' trap, using their technology without knowing they would eventually be harvested as a result, much of Prothean architecture seems to have been influenced by structures like the Citadel, blurring the line between what the Protheans built and what they found. In addition, at least some of their cities - those of Ilos in particular - were built upon the ruins of a previous civilization, the Inusannon, which had been wiped out by the Reapers 50,000 years prior.
 * Prothean Culture

The Protheans were also skilled at creating kinetic barriers. They built elaborate mass-effect defense grids using barrier curtains and a kind of personal defense shield that acted like an energy bubble, surrounding and levitating the individual who activated it. While inside, the person was impervious to harm but helpless, similar to a biotic stasis field. Perhaps the single most advanced piece of technology developed by the Protheans was the Conduit, a miniature, prototype mass relay designed to reach the Citadel from Ilos. This was a feat unequaled by any known contemporary or precedent race; given the complexity of the relays and other Reaper technology, reverse-engineering a mass relay is believed to be extremely difficult. Various Prothean ruins still survive on planets like Feros, Quana, and Therum, as well as many known yet unexplored sites in the Attican Traverse, with more unknown sites believed to exist elsewhere throughout the galaxy. While these ruins are surprisingly intact for their age, many were plundered long ago with time and generations of looters having picked their dead cities and derelict stations clean. Functioning examples of Prothean technology are rare. While hunting for rogue Spectre Saren Arterius, Shepard discovers Prothean data discs and ancient ruins on some uncharted worlds; the commander can even receive a Prothean "trinket" as a gift from Sha'ira, but as Liara T'Soni claims, solid evidence on the Protheans is scarce.

With the help of Shiala on Feros, Shepard also gains the Cipher, which is the key to fully comprehending the vision from the beacon. As the vision was meant for a Prothean mind, understanding it requires the individual to think like a Prothean - to understand their culture, biological instincts, history and ancestral memory. This "cipher" then allows the individual to unlock the true meaning of the images, and understand the vision as it was meant to be seen. According to Shepard, the Cipher's effect on the vision is quite subtle, and Liara's Prothean expertise is necessary to make sense of the images. The Cipher also grants Shepard complete knowledge of the Prothean language. In addition to the technology they left behind, the Protheans left a greater influence through their in-depth study of other races. Their work has had the greatest impact on humans and the hanar. In humanity's case, the discovery of Prothean ruins on Mars, which were home to a small data cache, introduced humans to element zero and eventually revealed the location of the Charon Relay. A Prothean ruin on Eletania can also yield an ancient recording from a Prothean data recorder that was implanted into a Cro-Magnon human. The hanar, who call the Protheans "the Enkindlers", credit them with giving the hanar sentience and language, and worship them as an elder race who allowed them to become civilized.

The Citadel was the Prothean seat of government, and the heart of their galaxy-wide empire. Although the Protheans were a single race, as they expanded and assimilated other spacefaring races into their empire, those servant races adopted the name "Prothean" for themselves as well. This assimilation was not always peaceful, as advanced species who attempted to deny or oppose their admittance into the empire were forcibly conquered and assimilated into Prothean society. The Protheans justified this cultural reconditioning by claiming that if the races who opposed them were actually stronger than the Protheans, then they would take the Protheans' place as the galaxy's dominant civilization. This ideology was also dictated by necessity. After the Protheans encountered hostile machine intelligences, they ultimately decided that all organic races should join together for the sake of survival. The beacons and the Eletania ruins suggest that, like the asari, the Protheans were comfortable with the notion of transferring data to an individual's mind. They invested heavily in their scientific research, a policy that eventually paid off, if too late to save their own species. Prothean society was heavily regulated; Javik mentions that playing games of chance was an offense punishable by death.
 * Prothean Government

Little is known of the Prothean military, it is known that they possessed fleets capable of defending their empire from threats. The flagship of the Prothean navy, Penumbra Apex, was equipped with a cannon similar in power to that of a Geth Dreadnought. Also, the Protheans produced Particle Rifles for their Infantry and had at least one Biotic near the end of the Reaper Invasion.
 * Prothean Military

While all evidence points to the Protheans being completely wiped out by the Reapers, this was not the case. The Reapers are believed to have attempted harnessing the genetic material from millions of Protheans to create a new Reaper. It is speculated by EDI that this attempt failed and so the Reapers decided to repurpose this substantial number of captive Protheans to suit the needs of the Reapers. Mordin speculated that these Protheans were indoctrinated and after a prolonged period of time as indoctrinated slaves, they were given cybernetic modifications to compensate for their growing lack of ability, which was a side effect of indoctrination. After several cloned generations, most likely during the centuries of Reaper genocide against the Protheans, the Reapers eventually decided to genetically rewrite these Protheans. These captives were transformed into an entirely new race which cooperated with the Reapers and would eventually be known to the citizens of the galaxy as the Collectors. Being a rarely seen species whose existence was questioned by most, the Collectors resided in the Collector base, a space station located in the galactic core and only accessible through the Omega 4 Relay. Nobody had ever returned from a trip through the Omega 4 Relay and a Collector had never been examined, thus the Prothean/Collector link had never been discovered. Collector technology, while very advanced, no longer resembles Prothean technology, the species likely having developed on its own after the Reapers completed the genocide of the Protheans, also adding to the belief that the Collectors and Protheans are unrelated. The Collectors are presumed to have been left with partial access to Reaper technology, possessing Husks, a Reaper IFF with which they could safely operate the Omega 4 Relay, and Reaper technology which protected the Collector base from the harshness of the galactic core.
 * Prothean Enthrallment

For the next 50,000 years, the Collectors would periodically travel to the Terminus Systems and make efforts to acquire seemingly unimportant items or small numbers of very particular types of individuals from certain species in exchange for their advanced technology. Whether the Collectors were always acting as directed by the Reapers during this time is unknown and the reasons for these transactions were never revealed by the Collectors. Immediately after the destruction of Sovereign, the Reaper known as Harbinger began directing the Collectors in the abduction of what would have eventually been millions of human colonists as part of the Reaper plan to create a Human-Reaper, part of a renewed attempt to begin the next cycle of extinction. Shepard took a team to the Collector base and ensured that the Collectors were wiped out, aware of the fact that the Collectors were once Protheans. This possibly eliminated the last remnants of the Prothean race.

Rachni
The rachni are a believed-extinct Type II Civilization race of intelligent insectoids that threatened to defeat and overthrow the Citadel races roughly two thousand years before the game's timeline.

Rachni workers are the smallest type of rachni. They appear as small green enemies and their main attack is a suicide explosion that releases toxic damage over a wide radius. Rachni soldiers are slower, but much larger creatures than Rachni Workers, with thin tentacles ending in little pods. Soldiers are the main defenders of rachni held areas and can cause toxic damage with their spit. Rachni brood warriors are rachni who are much larger and stronger than normal Rachni Soldiers. They are male gendered rachni and they have some biotic ability. Rachni Queens are the largest and most intelligent of the rachni.
 * Rachni Biology

Javik mentions the Protheans "uplifted" the Rachni (who were just animals in their cycle), turning them loose as living weapons; the Protheans burned two hundred planets when the Rachni inevitably went out of control, and were under the impression the Rachni were extinct.

The rachni, a species of spacefaring insects guided by a hive-mind intelligence, evolved on Suen, a planet tidally-locked to its red dwarf star. Life developed in a habitable terminator zone between hemispheres that were constantly scorched or perpetually frozen. The harsh conditions of Suen's surface forced the rachni to forage underground amid sprawling subterranean river systems. Sometime at the height of the Prothean Empire, the Protheans discovered the rachni and bred them as weapons of war, selecting for the most cunning and warlike queens and unleashing rachni swarms on their enemies. Eventually, the rachni became too difficult to control and turned on their Prothean masters. The Protheans attempted to eradicate the rachni and destroyed as many as 200 worlds before they were satisfied the rachni were extinct, but enough survived on Suen to replenish their population. As the rachni developed civilization, they established surface cities on Suen. Wrestling with the engineering problems of Suen's extreme surface environment may have given the rachni their first insights into how to build interstellar spacecraft. After achieving spaceflight, the rachni first traveled to the neighboring planet of Kashshaptu and discovered a crater there known as "the howling gulf", which featured an abundance of element zero. The rachni obtained samples of the eezo and studiously researched its properties, but would not develop FTL technology until centuries later.
 * Rachni History

They were first encountered by accident due to the activation of a long-range mass relay with a counterpart in what was, at that time, an unknown location. The extremely xenophobic rachni, angered by the encroachment of what it believed were inferior species upon its living space, counter-attacked, determined to destroy the perceived invaders. The rachni used their extensive research on element zero to reverse-engineer the FTL drives of the explorers' starships. They proceeded to construct FTL vessels of their own and rapidly expanded into the galaxy, ushering in the Rachni Wars. Negotiation was impossible with the rachni queens, who could not be contacted in their underground lairs on the toxic rachni worlds. It was assumed that the rachni were irredeemably hostile and could only be stopped through warfare, but the rachni had the upper hand and overwhelmed defenses with their sheer numbers. Eventually the krogan, discovered and elevated to civilization by the salarians due to their fighting prowess, hardiness, and high birth rate, were able to push back and eventually exterminate the rachni. With the conclusion of the Rachni Wars, the Citadel Council declared the rachni to be extinct; although in caution the Citadel Council left a listening post in the system to monitor for any survivors.

By the time of Mass Effect, rachni eggs had been found by a science team on a derelict ship and brought to the Peak 15 research labs on Noveria, where lax research regulations permitted a significant and dangerous amount of research and experimentation; the rachni were effectively brought back from extinction for the purpose of serving as weapons of war sold to the highest bidder. The rachni queen discovered by the player on Noveria explains that the rachni's tendency for extreme belligerence was not intrinsic to their nature, claiming to have been perverted by an outside force. The Queen promises that, were it permitted to live and escape from the facility, she would raise a peaceful new breed of rachni with respect for life and other life-forms. It is up to the player to decide whether the queen lives or dies. Cerberus created cloned rachni on Binthu as part of their super-soldier research. More rachni are encountered at Alliance listening posts on Nepmos and Altahe. After clearing the rachni out, Shepard discovers they were specimens shipped from Noveria by Cerberus, and tracks them back to a depot in the Gorgon system. The depot is overrun with rachni and there are no survivors. After killing the rachni, Shepard finds the logs of the station's commanding officer named Flores who was involved in the project. She angrily claims they treated the rachni like animals when they should have treated them like POWs and leaves a recommendation that Cerberus pursue other projects; the rachni are too smart.

If the rachni queen survives, it contacts Shepard in Mass Effect 2, saying that she managed to escape from Noveria and reestablish the rachni race. She also believes that the previous rachni were manipulated by the Reapers, and promises to help him fight them. Additionally, a news report reveals several mysterious ships have been sighted that match rachni designs; the Citadel Council has pledged to investigate these sightings. This appears to indicate that the rachni have progressed extensively in the two years since Shepard freed the Queen. The asari on Illium confirms that they have at least advanced sufficiently to be capable of repairing a damaged starship. If the Rachni Queen was destroyed, the rachni are effectively extinct again. A news report explains that a rachni cloning facility was discovered on Noveria, but no samples of the rachni have been found and the attempt to clone the rachni appears to have been unsuccessful.

In Mass Effect 3, a rachni hive is discovered by a krogan team led by Grunt, if he survived the suicide mission. The Reapers have once again enslaved the rachni: they have located a queen, indoctrinated her children (though not the queen herself) and converted them into Ravagers. If this queen is the one from Noveria, and Shepard chooses to free her, then she will send rachni workers to work on the Crucible project. However, if the Noveria queen was killed, the Reapers will construct an artificial queen, who, if freed, will prove untrustworthy after a few missions by withdrawing support and then killing Crucible engineers.

The rachni are territorial, determined to remain isolated from the rest of the galaxy. They normally inhabit extremely hazardous worlds, able to survive environments that kill most sentient species. Should their territory be invaded on purpose or even by accident, they respond with brutal force. However, many make the mistake of underestimating the rachni as mindless animals when in fact the rachni are an extremely intelligent sentient species. The rachni achieved space flight and a form of cryogenic suspension, developed weapons and carved out a huge swathe of galactic territory. Far from treating soldiers as disposable resources of the hive - rachni soldiers are carefully nurtured as part of the group.
 * Rachni Culture

The queens are the leaders of the rachni hive mind and provide guidance for the rest of their species. Their ways of perception, thinking and communications seem to be different from that of other races, and based upon a synesthesian perception of sound as both sound and color, and geared towards frequencies beyond normal sonic range, as well as a telepathic hivemind. They regard speech and thought as form of music, as shown by the strange metaphors used when attempting to communicate, for example, "songs the color of oily shadow". The speech patterns used by them in such occasions are also unusual; "When we speak, one moves all". They refer to their manner of communication as "singing", which soothes and nurtures their young, and this appears to colour their entire psychology - for example, the rachni speak of death as "the great silence", and refer to their homeworld as the "singing planet". The rachni ability to genetically share knowledge across generations makes queens a vast repository of information.
 * Rachni Government

Identified extinct races
The Milky Way Galaxy has existed for several billion years. In that time, countless races have attained sentience, forged civilizations, explored the depths of space, and then became extinct. These background races are often barely understood by the contemporary galaxy, which has pieced together scant details of a mere handful of ancient races through ruins and artifacts. Ancient races discovered across the galaxy each hundreds-millennium old are even less understood; while the ruins and artifacts they left behind may hint at their biology or technological advancement, in many cases the origins and even names of these races are not known.

The Prothean Javik briefly mentions several Type III Civilization spacefaring races who existed at the time of the Prothean Empire 50,000 years ago.
 * Ditakur - The aggressive ditakur wiped out the synril.
 * Enduromi - The enduromi conquered the vandomar.
 * Synril - The synril claimed to have found the path to eternal peace, but were wiped out by the ditakur.
 * Vandomar - The vandomar were conquered by the enduromi.

The arthenn are an extinct space-faring race that disappeared 300,000 years ago, and are mentioned in planetary surveys in Mass Effect 2. The planet Helyme in the Zelene system is believed to have been their homeworld. Helyme is now a "post-garden" world, with a gradually cooling climate and extreme seasonal shifts. It is theorized that the arthenn were wiped out by an out of control biological weapon, which destroyed all complex animal life on Helyme, but spared plant life. Landing on Helyme is prohibited for fear that the bio-weapon is still present. It could also be possible that the Reapers had wiped them out in a culling cycle preceding the Protheans (or, to be accurate, 4-5 cycles prior to Protheans). Evidence for a Reaper extermination can be found on a nearby planet where Arthenni mining locations have been destroyed in an orbital bombardment. In the rings of the systems gas giant there are remains of Arthenni space stations and of a small moon which has been destroyed by dreadnought-class weapons. Numerous other "post-garden" worlds can be spotted throughout the galaxy, most of them carrying evidence of extensive orbital bombardment. Many races are not even named. Several nearly destroyed Arthenn sculptures seen in concept art and screenshots of various post-garden worlds in Mass Effect 2 suggest several distinct similarities between the Arthenn and the Citadel keepers, suggesting that the keepers may have been developed by the Reapers using Arthenn DNA, much like how Collectors were developed using Prothean DNA.
 * Arthenn

The densorin were a race that existed at the time of the Protheans. At some point, they fought a war against the oravores. When the Reapers invaded the galaxy, the densorin attempted to pacify them by sacrificing their children to them, but this only allowed the Reapers to destroy the densorin more quickly.
 * Densorin

Little is known about the inusannon except that they warred with the thoi'han over colonization rights to the garden world Eingana 127,000 years ago. The wreckage of starships from both races litter the planet. The inusannon were eventually wiped out by the Reapers. According to Javik, the Protheans developed mass effect technology from information discovered in the ruins of their civilization. The statues on Ilos, initially thought to be Protheans, are actually inusannon.
 * Inusannon

The oravores were a spacefaring race that existed at the time of the Protheans. When they attacked the asari homeworld of Thessia to gain control of its vast resources, the Protheans stopped them. This event would later be remembered in asari mythology as when the goddess Athame wielded her sword against jealous gods who threatened the asari. The oravores also fought a war against the densorin.
 * Oravores

Little is known about the thoi'han except that they warred with the inusannon over colonization rights to the garden world Eingana 127,000 years ago. The wreckage of starships from both races litter the galaxy.
 * Thoi'han

The Thorian (also called Species 37) was an ancient sentient plant at least fifty thousand years old - its ability to hibernate for thousands of years makes its real age impossible to guess. The Thorian is a unique creature with mind-controlling and telepathic abilities, and a massive sensory network. It releases spores into the air that allow the Thorian to control those who inhale them, using pain to control their behaviour. These 'thralls' then tend to the Thorian and obey its will. According to the VI at the ExoGeni Corporation Headquarters, the Thorian is essentially "a weave of tendrils" that covers much of the surface of Feros with some sensory tendrils kilometres long, though in places they are gathered into nerve bundles or neural nodes. Though it is intelligent, the Thorian only regards other sentient beings as potential thralls. It describes itself as "The Old Growth."
 * Thorian

The zeioph are an extinct space-faring race mentioned in planetary surveys. Nothing is known about them, and the only known remains of their civilization consist of an enormous necropolis on the planet Armeni in the Knossos System. Human attempts to excavate and investigate the ruins have been stymied by Citadel policies that hold grave sites as sacrosanct.
 * Zeioph

The zha'til were a synthetic race that existed at the time of the Protheans. They originated when a race known as the zha implanted themselves with symbiotic AI technology to enhance their intelligence in order to survive as their homeworld became inhospitable. When the Reapers arrived, they subjugated the AIs, known as zha'til, who then seized control of the bodies of their masters and altered their genetic material at the deepest level, transforming the zha into synthetic monsters and their offspring into slaves. The zha'til proceeded to multiply into "mechanical swarms" that "blotted out the sky". With no other recourse, the Protheans sent the star of the zha's home system into supernova, destroying the zha'til entirely.
 * Zha'til

Reapers
Reapers are a hyper-advanced machine race believed to be the creators of Mass Relays and the Citadel, resembling the species that their initial genetic material has been taken from, that periodically awaken to destroy all advanced organic life in the galaxy and are the primary antagonists of the Mass Effect trilogy. Preventing a technological singularity is the prime-directive of the Reapers; they fear rampant technological growth will end with artificially created races destroying all organic life; they allow civilizations to reach a certain apex before setting things back to zero. A myth common to several cultures in the galaxy, Reapers were once imagined as space monsters that consumed entire stars. Archeologists who searched for the sources of such myths found little besides the themes of all-consuming devils that are common to primitive cultures. Although accurate information about the Reapers remains scarce, the galaxy now knows that the Reapers are not a myth—they are a real and devastating threat.

Reaper Origin
The term "Reaper" is not actually a self-designation. According to Sovereign, a Reaper vanguard left behind to ensure the Reapers' return, it is a Prothean name given to them, stating they have no name and that they "simply are". However, it is revealed by the character Legion in Mass Effect 2 that Sovereign referred to itself as Nazara and that the Reapers are known as the "old machines" among the geth. The Reapers hibernate in the dark space that lies beyond the galaxy's outer rim, and the Citadel itself is a gigantic mass relay that allows them to return to the galaxy. The Citadel's location at the mass relay network hub, along with its formidable defenses, make it a seemingly ideal location for the capital of galactic civilization. Upon the Citadel's activation however, the Reapers quickly attack the Citadel and seize control of the mass relays, decapitating the government command structure and isolating individual systems. With any advanced organic civilizations in disarray, the Reapers then proceed with their genocide by methodically invading each system, exterminating or enslaving populations as they advance. This cycle of destruction has been repeated every 50,000 years for at least 37 million years; however, the Reapers have no known motive for this act beyond it being for reasons organic minds cannot comprehend. The primary plot of the game involves a race against time to prevent the Reapers' return.

The Citadel races have classified the known variants of Reapers into four types: Capital Ships are Sovereign-class Reapers two kilometers in length. They typically target the dreadnoughts, defense installations, and industrial cities of organic civilizations. Experts believe the Reapers harvest a single species of organics during each cycle of extinction to create these massive ships. Some capital ships are capable of launching small drones equivalent to fighters. Destroyers are 160 meters long and, in astounding numbers, make up the bulk of the Reaper fleet. They engage cruisers and other, smaller ships, as well as communications posts and enemy command centers. Due to their smaller size, Destroyers are significantly more agile and maneuverable than the larger Capital Ships. In exo-atmospheric engagements, they are capable of directly landing on larger spacecraft and attacking at point-blank range. Research suggests destroyers are created from those species that are not harvested to make capital ships. Troop Transports carry husks to unconquered planets and bring victims of the harvest to Reaper processing centers. They vary in length from 200 meters to one kilometer, but, unlike capital ships and destroyers, do not appear to be self-aware. Instead, other Reapers operate troop transports remotely. Processors, also called "slaughter ships", are mobile centers for mass DNA harvesting. Like troop transports, processors appear to be remotely operated by sapient Reapers.
 * Reaper Design

Sovereign, the first Reaper encountered, bore a superficial resemblance to a reaper cuttlefish, with a bulky semi-cylindrical body, a tapering plate over the rear and a mass of metallic "tentacles" extending from its front end, in addition to six jointed legs extending from its body. The physical design was based on the physical appearance of the Leviathans, the race that dominated the galaxy before the time of the Reapers. When the Reaper fleet is revealed in dark space they are all shown with this basic design. However, one Reaper in the foreground shown when Harbinger awakens the fleet seems to resemble a scarab beetle but with great diversity in tentacle number, shape, and orientation, some with extended heads and others (particularly Harbinger) having multiple glowing eyes. This diversity is presumably due to the Reapers' reproduction method, in which vast numbers of a single species are harvested, melted down into a raw genetic paste, and then used to construct a "larva" that takes on the characteristics of the species from which it was created. It has been confirmed that the "larval" Reaper seen in the game is in fact the "core" of a Reaper, and would have later been encased in a similar shell. This also explains the relatively small size of said "baby" Reaper.

Sovereign's design appears to have influenced the 'heretic' geth. This is not surprising, as these geth worship the Reapers as "gods", considering them to be the epitome of independent AI. Wherever the heretic geth become entrenched they build monuments to the Reapers resembling Sovereign's 'tentacles' around a glowing orb, and genuflect. Sovereign was apparently insulted by the adoration of such simple, base synthetics, but it did see their value as pawns and possible replacements for the flawed and organic keepers.

In Mass Effect, it is at first believed that Sovereign is simply a massive dreadnought of unknown origin about two kilometers long (the largest warship class within game canon is standardized at one kilometer) controlled by rogue Spectre Saren Arterius. Later, Sovereign reveals itself to actually be a huge sentient ship, a Reaper, and the true power behind Saren. Reapers generate an "indoctrination" field, an array of signals that progressively and permanently damage higher-order functions in organic brains. Sovereign uses this method to exert influence over its organic charges, to varying degrees (total mind control on one end, suggestion on the other), including Saren Arterius. Sovereign's design resembles a squid, with a long round hull strong enough to take no noticeable damage when it rammed into a dreadnought-class vessel, and large multi-jointed limbs equipped with powerful weapons. In conversation with Commander Shepard, Sovereign claims that the Reaper race is "infinite"; has "always existed"; and has no creators. Being a mechanical race, these claims are irrational, but still Reaper psyche is logically bound (It is possible that the Reapers were once organic and merged themselves with machines).
 * Reaper History

In Mass Effect 2, a Reaper named Harbinger directs the Collectors to capture entire human colonies. The genetic material (liquefied human bodies) from the captured colonists is used to create a human-based Reaper. It is made clear in Mass Effect 2 that Reapers are modeled after the organic race that constitutes a Reaper's organic components. In the subsequent conversation that follows the revelation of the existence of a human-Reaper "larva", it is implied that the harvesting and cyclical exterminations of all sapient life committed by the Reapers is part of a "reproductive process" whereby the Reapers acquire material needed to create new Reapers. The character Legion describes a Reaper as "one ship, one will, many minds", insinuating the minds of the organics used in a Reaper's construction are still active in their new form, though it may also suggest a geth-like collection of programs.

At the end of Mass Effect 2, Harbinger is seen activating the dormant Reaper fleet, showing a few hundred others which share Sovereign's basic cuttlefish-like appearance. The fleet, presumably numbering in the hundreds or thousands or even millions (although only between two and three hundred are shown in a brief scene involving Harbinger and the Reapers awakening), appears to be moving towards the Milky Way, thus setting the stage for Mass Effect 3. In Mass Effect 3, the Reapers attack Earth and the rest of the Milky Way, as was previously speculated by Shepard and others.

At the end of Mass Effect 3, it is revealed that the Catalyst, the final component of the weapon meant to destroy the Reapers, is actually an ancient artificial intelligence that embodies their collective consciousnesses and memories. The Catalyst explains that it was created by the Leviathans, who observed that species under their enthrallment were felled by their synthetic creations. To prevent such events from happening, they created the Catalyst to oversee relations between organics and synthetics, and to preserve organic life at any cost. All of the Catalyst's efforts were in vain, and it chose to resolve this problem by putting in place a system that would prevent any advanced civilization from reaching that point.

The Reapers took form of the Catalyst's solution. The design was based on the physical appearance of the Leviathans, while the Catalyst was able to control them. However, they failed to recognize the Catalyst as nothing more than a tool to fulfill its mandate, and eventually their creation betrayed them, deciding that the Leviathans also risked conflict with synthetics. It gathered an army of pawns, in a similar fashion to the Collectors, slaughtered its creators, and forcibly processed them into the first true Reaper, Harbinger. The surviving Leviathans went into hiding, observing the Reaper cycles for countless eons. The solution also dictated that all space-faring organic and synthetic races must be harvested with millions of bodies and minds from each race being processed and converted into new Reapers. By doing this, the Reapers preserve the harvested races, while allowing the more primitive races to advance and ensuring that annihilation of all organic life by synthetics was averted. Each cycle ends with the birth of a new Reaper created in Harbinger's image. Depending on the ending, Shepard may all destroy all synthetic life, replace the Catalyst's AI with the his/her consciousness to order the Reapers to retreat, or use him/herself as a template to merge organic life with the Reapers' semi-organic technology, rendering their purpose meaningless (as synthetic and organic life have become one and the same).

If the Control ending is chosen, Shepard directs the Reapers to restore the mass relays and help rebuild the galaxy. They become a supreme military force that guards the galaxy from anything that could harm its people. If Synthesis is chosen, the Reapers help rebuild the galaxy of their own accord, and share the collective knowledge of countless alien cultures that came before.

Alternatively, if Extended Cut is installed, Shepard may choose to reject all of the Catalyst's options, thus allowing the Reapers to complete their harvest of all advanced civilizations.

During their invasion at the end of each cycle, the Reapers gather and "process" vast numbers of individuals from each of the galaxy's sentient space-faring races. Victims who cooperate with or are captured by Reaper husks are rounded up into "camps," where the husks select individuals deemed fit for processing; it is believed that the husks use scent or chemical receptors to analyze the genetic composition of victims. Those who are deemed unsuitable are turned into more husks. Individuals who are determined to be suitable for processing are loaded onto Reaper Processors, where they are ushered into single-person pods. Like a slaughterhouse, the interior of the Processor is designed to prevent any visual or auditory contact between individuals being processed. Once in the pods, the victims are dissolved into a raw genetic "paste" for ease of transport. This paste will then be used in the construction of a newborn Reaper, with the victims' minds being preserved to form the Reaper's gestalt consciousness. Even with all the Reapers' power, harvesting every sapient species in an entire galaxy can take decades or even centuries. The most time-consuming part of the process is gathering DNA from the population. The only known facilities used for Reaper construction are located on the Citadel and within the Collector Base in the galactic core.
 * Reaper Culture

Available information suggests that a single race is harvested during each cycle to produce Reaper Capital Ships; it appears that other space-faring races harvested during the cycle are used to produce Destroyer-class Reapers. Exactly how or why this distinction is made is unknown. The rate of killing during a harvest is staggering - during the invasion of Earth, at least 400 Processors were present, and the number of humans processed each day was estimated at 1.86 million. At such a rate, the entire planet would be depopulated in a decade. As a "back up" option, the Reapers were capable of using the Collectors - a slave race genetically engineered from the Protheans - to gather genetic material in their stead. The Reapers are only known to have used this option once, when they used the Collectors to conduct mass raids on human colonies as part of a plan to create a human-based Reaper.

Reapers and their technology have a strange effect on organic beings. Both Dr. Shu Qian and Edan Had'dah begin acting oddly after coming into contact with the "artifact" they found. This mental manipulation is known as indoctrination; an insidious means of corrupting organic minds, "reprogramming" the brain through physical and psychological conditioning using electromagnetic fields, infrasonic and ultrasonic noise, and other subliminal methods, consistent with frequencies that trigger feelings of awe and fear in victims. The Reaper's resulting control over the limbic system leaves the victim highly susceptible to its suggestions. Organics undergoing indoctrination may complain of headaches and buzzing or ringing in their ears. As time passes, they have feelings of "being watched" and hallucinations of "ghostly" presences. Ultimately, the Reaper gains the ability to use the victim's body to amplify its signals, manifesting as "alien" voices in the mind. Put simply, any organic being who is in close proximity to a Reaper for too long comes to believe the Reapers are correct in their goals and will do anything to serve them. Gradually the mind is eroded until the individual becomes a mindless slave no longer capable of independent thought. According to the Leviathans, indoctrination was inspired by the their ability to control organic races through "artifacts". Unlike Reaper indoctrination, Leviathan enthrallment must be constantly maintained, and does not cause long-term mental damage.
 * Reaper Indoctrination

Indoctrination can create perfect deep cover agents. A Reaper's "suggestions" can manipulate victims into betraying friends, trusting enemies, or viewing the Reaper itself with superstitious awe. Should a Reaper subvert a well-placed political or military leader, the resulting chaos can bring down nations. Long-term physical effects of the manipulation are unsustainable. Higher mental functioning decays, ultimately leaving the victim a gibbering animal. Rapid indoctrination is possible, but causes this decay in days or weeks. Slow, patient indoctrination allows the thrall to last for months or years. Sovereign could partly control the rate of this process as seen with Saren; in order for him to serve the Reaper efficiently, Saren needed a measure of free will. This eventually convinced him that the only way to preserve organic life was to submit to the Reapers provided they could prove themselves useful. Only beings of immense mental strength, such as asari matriarchs, can resist indoctrination, and even then, their resistance only lasts a short time and only forestalls the inevitable. Matriarch Benezia chose to die rather than risk falling under indoctrination again, and when Saren finally rebels against Sovereign, he kills himself to prevent doing any further damage to the galaxy. This indoctrination is permanent (with the single possible exception of Shiala) and is one of the most insidious weapons of the Reapers. Even more horrifying is that the indoctrination field remains active even if the Reaper is largely disabled and incapable of action. A Cerberus science team was indoctrinated by being inside a Reaper that had otherwise been floating derelict for 37 million years, its only obvious activity being mass effect field generation.

Even without their indoctrinating influence, Reapers are immensely powerful warships and their technology is devastating. Sovereign’s destructive power was unrivaled in the known galaxy. Each of the "tentacles" extending from its bow was equipped with a powerful "magnetohydrodynamic" weapon which ejects a stream of molten metal at a fraction of the speed of light which could tear through a cruiser in a single sustained burst. Its gigantic spinal-mounted gun was able to rip through the hulls of even the largest of dreadnought-class ships with ease, effortlessly penetrating their kinetic shields. Sovereign's defences included powerful shields that could block the projectiles of an entire fleet, along with an incredibly strong hull. Though they are sentient machines, the Reapers have habitable interiors that can transport a crew, either to help spread their indoctrinated slaves or to allow these slaves to tend to them, probably both. Speculation in the Codex suggests that each individual Reaper has a massive element zero core which, coupled with the likely enormous quantities of energies at its disposal, allows it to generate the staggering mass effect field needed to land on a planet.
 * Reaper Technology

However, the Reapers are not invincible. When the Reapers go into states of hibernation between cycles, they are vulnerable. By taking refuge in dark space, the Reapers ensure they will not be discovered by accident and destroyed while they wait for their vanguard to open the Citadel mass relay. A concentrated effort by the fleets of organic races could also destroy a Reaper even if it is at full power; the humans' Systems Alliance fleet was able to destroy Sovereign quickly when its shields and weapons were disabled.

The Reapers are technologically superior to the organic species of the galaxy—but the degree of that superiority is a matter of debate in the intelligence community. The Reapers' thrusters and FTL drives appear to propel them at more than twice the speed of Citadel ships. Estimates of their location in dark space suggest they can travel nearly 30 light-years in a 24-hour period. Reaper power sources seem to violate known physical laws. Reapers usually destroy fuel infrastructure rather than attempting to capture it intact, indicating that Reapers do not require organic species' energy supplies. Consequently, the Reapers attack without regard for maintaining supply lines behind them, except to move husks from one planet to another. Unlike Citadel ships, Reapers do not appear to discharge static buildup from their drive cores, although they sometimes appear wreathed in static discharge when they land on planets. The main gun on a Reaper capital ship dwarfs that of the Alliance's Everest-class dreadnoughts. No dreadnought has yet survived a direct hit from the weapon. Estimates put its destructive power anywhere from 132 to 454 kilotons of TNT. Even if the target is hardened, as in the case of a surface-based missile silo, the gun can instead bury the target beneath molten metal. Precise targeting computers and correctors also give the Reaper weapons a longer effective range than organics' dreadnoughts or cruisers. The kinetic barriers on a Reaper capital ship can shrug off the firepower of a small fleet. Weapons specifically designed to overcome shields, such as the Javelin, GARDIAN lasers, or the Thanix series, can bypass the barriers to some degree. The difficulty is getting close enough to use them—the surface-mounted weaponry on Reaper ships, similar in principle to GARDIAN, presents an effective defense against organic species' fighters.
 * Reaper Capabilities

Although clearly technologically superior to the Citadel forces, the Reapers have experienced casualties in the battles across the galaxy. This indicates that, theoretically, with the right intelligence, weapons, and strategy, the Reapers could be defeated. Unlike the mass effect relays that they created, Reapers do not have quantum shields. Locking itself down at a quantum level would leave a Reaper unaware of its surroundings until the shielding deactivated. Instead, Reapers rely on kinetic barriers. In the case of a Reaper capital ship, these kinetic barriers can hold off the firepower of two dreadnoughts simultaneously, but three clearly causes strain, and four typically results in destruction. Weapons designed to maximize heat damage, such as the Thanix series, show better results against the Reapers than pure kinetic impacts. The barriers of a Reaper destroyer are less formidable than those of a capital ship. It is possible for a single cruiser or many fighters to disable or demolish a destroyer if they can get within range before they are themselves destroyed. The Reapers' energy sources are not infinite. For example, to land on a planet, a Reaper must substantially reduce its mass. This transfer of power to its mass effect generators leaves the Reaper's kinetic barriers at only partial strength. Sovereign was destroyed while assuming direct control over Saren. The feedback from Saren's death seemed to entirely overload Sovereign's shields. Current Reapers do not seem to suffer from this design flaw. Reaper capital ships can turn faster than Citadel dreadnoughts, but to do so, they must lower their mass to a level unacceptable in combat situations. Consequently, it is possible for a dreadnought to emerge from FTL travel behind a capital ship, then bring its guns to bear faster than the Reaper can return fire. This is a poor tactic, however, against Reapers flying in proper formation.
 * Reaper Vulnerabilities

Entire worlds and civilizations subject to Reaper occupation that are neither suitable for indoctrination or genetic-processing are "re-purposed" into expendable synthetic-organic "zombie" invasion forces designed for leveraging "psychological warfare" against organics; this process allows Reapers to freely wage wars without supply lines or other logistical considerations. The Prothean Javik reveals that during his war, the Reapers turned the Protheans own children into shock troops and suicide attackers, who were shocked by the monstrosities they've encountered, and that "every battle with the Reapers conjured a new nightmare."
 * Reaper Military

Abominations act as suicide troops, exploding when in range of targets. The Abomination will start to glow and emit flames as it charges towards its target, and will explode when it gets close.

Banshees are the corrupted asari often found leading a Reaper strike force. The Reapers create them specifically from asari with active or latent predispositions to becoming Ardat-Yakshi, a rare neurological condition that enhances the asari's biotic power while causing the immediate death of anyone she mates with. Lumbering as though in constant pain, the emaciated banshees are surprisingly durable opponents. They are devastating biotics able to hurl lethal balls of energy and create shockwaves as they regenerate. What Alliance military finds most disturbing is the Banshee's ability to spawn her own warp field and seemingly teleport during combat. Although their wails have no apparent physiological effect, the psychological impact is undeniable. When banshees die, their Ardat-Yakshi genetics twist against them, causing a biotic implosion to ensure they evade capture.

Brutes are hulking amalgamation of turian and krogan victims of the Reapers. Because tissue from dextro-protein species like the turians is incompatible with levo-protein species like the krogan, implants regulate the brute's body chemistry to combat organ rejection. It is the fusion of turian military skill and krogan blood rage that makes the brute such a formidable enemy, capable of destroying armored vehicles to get to the soldiers inside. Troops are advised to keep their distance, and, whenever possible, not engage a brute alone.

Cannibals are front-line Reaper units created from corrupted batarians. The nickname refers to their propensity to devour the bodies of fallen comrades. This triggers a biochemical process through which the cannibals simultaneously heal themselves and grow new chitinous armor. The transformation also appears to give cannibals a greater awareness of their surroundings, leading to more strategic behavior and careful use of battlefield cover.

Harvesters in flight nearby is one of the first indications that a Reaper invasion is underway. Their massive wingspan allows them to quickly cover the distance between them and their prey. In the Harvester's mouth are two heavy guns that fire in an alternating pattern. The Harvester's most fearsome quality, however, is that its appearance guarantees that Reaper ground troops are not far behind.

Husks are the aggressive, mindless foot soldiers of the Reaper armies. They are created by impaling either living or dead humans on mechanical spikes that rapidly extract water and trace minerals and replace them with cybernetics. These cybernetics reanimate the lifeless flesh and tissue, transforming the bodies into horrifying killing machines. The Reapers use large groups of husks to overwhelm the enemy. The husks' inability to feel pain, as well as their tendency to attack in groups, makes them particularly deadly adversaries.

Marauders are harvested turians that command and protect other Reaper troops. The lean, armored creatures present a significant threat in and of themselves, but they are especially dangerous when leading a Reaper task force. Alliance marines have observed marauders fortifying husks and cannibals by enveloping them in a ribbon of energy that forms a scabby shell of armor. For this reason, when Alliance soldiers encounter a marauder alongside husks or cannibals, standing orders are to target the marauder first.

Praetorians are slow-moving flying construction; it consists of thirty deformed Husks fused together, and has a strong barrier and powerful armor, giving it high durability. Commander Shepard engages a Praetorian on two occasions: once at the end of the mission on Horizon, and once during the escape from the Collector Cruiser. Several Praetorians were also involved in the attack on the Normandy SR-2.

Ravagers are former rachni that the Reapers have transformed into heavy artillery through a process of implantation and genetic modification. As walking organic turrets, they can sustain and inflict considerable damage. Ravagers bear egg sacs that continuously spawn swarmers. If the sacs are destroyed, either during combat or upon the ravager's death, their entire contents burst forth to charge the enemy and explode on contact. A dead ravager expels a caustic gas and an acidic puddle. Alliance scientists have theorized that it is easiest for the Reapers to maintain control over units of rachni genetic extraction because of the species' neurological predisposition for hive-mind consensus.

Scions are made from three Husks fused together and grafted around a single mass effect/biotic weapon on the left arm. The blue 'sacks' on their backs contain redundant organs and element zero sources to provide power for their weapons and shockwaves. Scions operate alone or in pairs, hanging back as Husks and Abominations rush ahead. Less mobile than other Husk variants, Scions provide ranged fire support, lumbering behind the wave of attackers while firing weapons and discharging biotic attacks.

Reaper War
Faced with utter annihilation, military planners have considered extreme solutions in their quest to stop the Reapers. The two most plausible are the destruction of mass relays and the use of starships as suicide weapons. Destroying a mass relay to stop the Reapers' advance is infeasbile. Although it has recently been proven that mass relays can be destroyed, a ruptured relay liberates enough energy to ruin any terrestrial world in the relay's solar system. It would take too long to evacuate the millions or billions of people living near each relay, and the Council is unwilling to sacrifice that many lives when combat stands a chance of saving them. Even if a garden world were to survive the relay's destruction, the Reapers have infinite patience. They traveled out of dark space using conventional FTL—travel within galaxy is not an insurmountable barrier. Meanwhile, starships are too costly to be used as projectiles, given that it would take many collisions to seriously harm a Reaper. Some armchair admirals suggest that a single starship traveling faster than light could obliterate a Reaper capital ship, but all ships based on mass effect technology possess hardwired safety features to prevent FTL collisions. If a ship's FTL plotter finds a significant object in the path of a planned jump, the FTL drive refuses to fire in the first place. This is not a perfect safety feature—the sensors can only scan for objects within a reasonable distance at light speed, and a navigator must plot the rest of the course—but it is so inherent to the FTL warm-up process that removing it is nigh impossible. Cynical intelligence analysts note that the secret of mass effect technology, including that safety system, has always been attributed to the Protheans—just as the mass relays were.

The Reapers took Earth in a matter of hours. The Alliance knew the first wave would arrive from batarian space, but they were unprepared for the speed and scale of the attack. The Reapers bypassed the Sixth and Seventh Fleets at Terra Nova and Eden Prime, flying straight from relay to relay where they could neither be tracked nor intercepted. The tactic was unexpected, since the navies of organic species would never risk coming out of FTL within combat range or leaving enemies at their backs to threaten supply lines. At Arcturus Station, more than a dozen Reaper capital ships engaged the Alliance's Second, Third, and Fifth Fleets. This was mere screening for the main force. Dozens more capital ships continued through the Charon Relay, where the First Fleet had been lying in wait but was soon destroyed. The Fourth Fleet, near Earth, had a few minutes of advance warning. It stood no better chance. After destroying Earth's comm buoys, smaller Reaper destroyers wiped out all GPS and communications satellites in Earth's orbit and cut the undersea fiber-optic cables that linked the continents. Earth's resistance now relies on outdated radio towers and a few quantum entanglement communicators. whose matched pairs happen to be on other continents or outside the Sol system. Communication is so limited that the fate of entire nations remains unknown. The capital ships bombarded defense installations and industrial centers, annihilating entire cities with populations in the low millions, including Adelaide, Hamburg, Al Jubail, and Fort Worth. Meanwhile, Reaper destroyers descended into the atmosphere to melt roads and capture population centers with minimal loss of life. This is not an example of the Reapers being merciful. More likely, they are herding their prey to make the coming harvest that much easier.
 * The Fall of Earth

For every thousand batarian refugees, there are a thousand and one stories about how the Reapers invaded the batarian systems. A few elements are common to almost every version, however. The Reapers arrived first in the Vular system and immediately destroyed its communications network. The Hegemony's Department of Information Control blamed the loss of signal on space weather, but scrambled ships to the system nonetheless. Within a day, Reaper capital ships appeared in the Harsa system and descended on the batarian homeworld, Khar'shan. For all the rhetoric about the Hegemony's military prowess, their response to the Reapers was uncoordinated. Moments after the information minister took to the extranet and announced that unknown ships were destroying all traffic near Khar'shan, the defense minister declared there was no reason to panic. The planet's comm buoys were destroyed next, creating an ominous silence that has persisted ever since. Fearing they were next, batarian colonies across Hegemony space began evacuations. So many refugees poured into the human-occupied Exodus Cluster that Systems Alliance officials at first thought the batarians were invading. More systems have gone dark as their comm buoys were destroyed, and millions more batarians, trapped on their planets, sit waiting for the Reapers.
 * The Fall of Khar'shan

The Reapers' first attack on turian space followed an age-old maxim: hit them where it hurts. A populous colony dating back centuries, Taetrus was already embedded in the turian psyche as the site of the worst terrorist attack in turian history. Wounds were still raw from the Vallum Blast, in which a separatist revolutionary slammed a starship into the colony's capital, killing more than a hundred thousand turians. Hierarchy forces responded with a massive invasion of the planet to stamp out the separatist movement. It was a catharsis for the turians, reassuring them that heroes would always triumph over evil. And so the Reapers struck Taetrus first. By the time Taetrus went dark, the turians had already learned that the batarians and humans were under attack. The Hierarchy responded with what they believed was overwhelming force, only to walk into a trap. Reaper ships were waiting on the other side of the relay to Taetrus, and they released devastating firepower the moment the fleet emerged. Turian leaders observing the one-sided battle were faced with a choice: reinforce their side of the relay to defend against a Reaper invasion, or throw more resources into an offense. With soldiers and civilians alike clamoring for retribution against the Reapers, the turians continued the assault. The Hierarchy sent warp bombs through the relay to clear a path, fighting tooth and talon to inflict casualties against the Reaper fleet. It was a valiant effort, but doomed. The Reapers emerged victorious from the relay and began broadcasting a signal to turian comm buoys—images of Vallum, Taetrus's capital, once again a smoking wreck. The fight for turian space had begun.
 * The Fall of Taetrus

When Taetrus fell, the turians knew little about the Reapers except that they wanted to enrage the turians. Staying calm, the turians massed force around Palaven, their homeworld. Fleet Admiral Irix Coronati, in what became known as the "Fifteen-Minute Plan," stationed only two carriers, Undaunted and Resolute, near the system's relay. When the Reaper fleet emerged, the carriers launched swarms of unmanned fighters and spy drones. These were quickly destroyed, but the drones transmitted vital data on the Reapers' effective range, fleet composition, and exact location. The turians' other ships then deployed to defend the system in earnest. Knowing that the Reapers' weapons had a longer effective range than any of his own, Coronati made a short, daring FTL jump—landing his dreadnoughts in the middle of the Reaper fleet. The dreadnoughts then turned to line up their main guns on the Reapers, which also needed to turn to fire on the turians. This ploy used the Reapers' size against them—because they could turn faster, and their concentrated firepower downed several Reaper capital ships. The Reapers countered instantly. Their destroyers performed a jump of their own to the skies above Palaven, beginning orbital strikes of turian cities. The turians, forced to defend the planet, found themselves in a pitched battle far from the relay, from which emerged a seemingly endless line of Reaper ships. After massive casualties, Coronati ordered retreat. The turians insist that Palaven is not lost—the battle has merely moved to the ground. Reaper troop transports have dumped hordes of husk to capture Palaven's inhabitants, but met with little success. Reaper capital ships are destroying city after city. But much of the turian fleet is still operable, and the citizenry is heavily armed. The turians refuse to be intimidated.
 * The Battle of Palaven

The quarians' plan to take back their homeworld was risky, and could easily have led to their annihilation if a peaceful solution had not been found. In an initial battle against the Reaper-upgraded geth ships, the quarians found their Heavy Fleet and a portion of the Patrol Fleet outmatched. To stave off defeat, the quarians retreated at FTL speeds to rally with the Civilian fleet on the far side of Rannoch's sun, Tikkun. Temporarily hidden, but with only minutes of advance warning should a geth scout spot them, the quarians planned counterattacks to disrupt the geth link with the Reapers. First preying on a damaged geth dreadnought, the quarians followed by sending strike teams to Rannoch's surface to destroy the Reaper that was transmitting improved software to geth forces. When the Reaper uplink was disrupted, the geth suffered momentary downgrades in response time and intelligence, allowing the quarians to press their advantage. But emergency order from Commander Shepard and Admiral Shala'Raan vas Tonbay broke off hostilities before the geth's full capabilities were restored. It is to the quarians' credit that all three fleets obeyed the order to cease fire, even the Civilian Fleet, which had little combat experience. The geth, for their part, bore no ill will towards enemy combatants and broke off hostilities with perfect discipline. It remains to be seen how the geth and the quarians will manage to coexist on Rannoch. For now, they have committed their considerable military forces to repel the Reapers. Given the long-lasting animosity between the geth and quarians, it is possible that the Reapers did not plan for the possibility of such an alliance and will be unprepared to contend with both armadas.
 * The Battle of Rannoch

Councilor Udina's attempted coup will no doubt be analyzed for generations to come, but a clear picture is beginning to merge. Udina had contacted Cerberus to coordinate what was intended to be a bloodless takeover of the Citadel, in which he would force the other councilors to grant him emergency powers so that he could command the Citadel Fleet. He would then direct the fleet to liberate his homeworld, Earth. The plan fell apart early when Executor Pallin and the salarian councilor caught wind of it. In defense of the plan, the Illusive Man dispatched his top assassins, commanded by Kai Leng, to kill them. Udina had little choice but to support the assassins with an armed force sufficient to hold the Citadel. Captured confidantes have indicated that Udina and Leng's alliance was relatively fragile: Udina may have planned to turn on Cerberus once the fleet was his to command, and Leng departed when he calculated that Udina would not succeed. Persistent rumors suggest that Udina might have been a high-functioning victim of Reaper indoctrination. His actions played right into the Reapers' plans: even if the coup failed, it would damage Citadel governance. If it succeeded, his plan to retake Earth would likely have turned into a military blunder that Council forces could ill afford. However, there is no direct evidence of his indoctrination, nor obvious opportunity. It is more likely that Udina acted out of desperation, and in doing so, cost humanity its councilor.
 * The Cerberus Coup

The assault on Thessia did not go as smoothly as the Reapers' strikes against other races. While other species met the Reapers head-on, the asari resorted to dangerous hit-and-run tactics to harass their attackers. By engaging in guerilla strategies—blast a Reaper ship, then jumping to FTL where they could not be tracked—the asari forced the Reapers to remain on the defensive. Unfortunately, the Reapers' greater numbers allowed them to accept certain losses, so they soon ignored the attacks against them and began orbital bombardment of Thessia. This in turn forced the asari to defend their homeworld with a more traditional stance, facing the Reaper forces directly. As soon as the Reapers landed on Thessia, the harvesting began. A swift and brutal slaughter of the asari ground forces followed. Resistance from trained biotics barely slowly the attackers down. In the end, Thessia's minimal military forces, combined with unpreparedness in the face of an overwhelming enemy, resulted in the fall of the planet.
 * The Fall of Thessia

The turian and krogan counterattack on Palaven combined deception, courage, and tenacity. First, the turians leaked a false battle plan that drew on the same tactics they used at beginning of the assault on Palaven. Then the dreadnought Indomitable faked a problem with its drive core, coming out of FTL near Palaven's moon, Menae. Three other dreadnoughts and their attendant fleets deployed to assist Indomitable, a tempting target that drew the Reaper capital ships away from Palaven. Turian troop transports then entered Palaven's atmosphere to release shuttles, gliders, and individual soldier capsules. The Reapers did not understand the seriousness of the threat at first—those that detected the landing crafts sent husks and Collector swarms to intercept them, but little more. This allowed krogan commandos to link up with Palaven's resistance and hand off their payloads—warp bombs and fission weapons. In simultaneous strikes across the globe, Reaper ships began to explode. Turian resistance members had managed to smuggle the bombs inside when the Reaper processing ships, troop transports, and even destroyers and capital ships had opened their structures to indoctrinated turian leaders. Large swaths of territory fell back into turian and krogan control. News of the victory gave a much-needed boost to the morale of the turian resistance and the galactic public. But the action was not without sacrifice. Turian insurgents gave their lives to ensure the explosives detonated, and the processing centers they destroyed were full of civilians who died just as surely as if they had been harvested. Of the dead, General Minin Resvirix said, "Whatever they were in life, their deaths had no equal. They are worthy of joining the spirit of Palaven itself."
 * The Miracle at Palaven