Psyker

Psykers are individuals with psychic abilities in the Warhammer 40,000 fictional universe. Psykers draw their powers from the Warp, an immaterial dimension with huge potential energy, but one that is also full of peril, and hence they are often in danger of daemonic possession and insanity.

Psykers of Different Races
Most races in the Warhammer 40,000 universe employ some form of psykers to their use on the battlefield; some are inevitably more potent than others. There are three exceptions to this: the Tau, the Dark Eldar and the Necrons. The Dark Eldar "view those who use psychic powers as amusing playthings" and can't risk their souls being devoured by Slaanesh (a daemonic entity that could be attracted by psykers), the Necrons consider the Warp to be anathema due to the influence of the C'tan, and the Tau have virtually no warp presence. It could be because of the history of the Dark Eldar they shirk away from using psykers knowing the damage that widespread psionics can have.

The Imperium of Man
The Imperium employs various 'psykers' throughout the Imperium of Mankind in various roles.Imperial Guard Regiments and Space Marine Chapters effectively use psykers in combat roles. Astropaths provide faster than light psychic communication. The psychic Navigators are required to cross safely through the Immaterium using the Astronomicon as their guiding beacon. The Astronomicon is the psychic manifestation of the Emperor's will as he sits upon the Golden Throne. Thousands of psykers are sacrificed daily to empower the Golden Throne and sustain the life of the ever dying, ever deathless Emperor of Mankind. However, the Imperium of Man also executes countless psykers as they are seen as mutants, potential threats, or gateways to Chaos.

Astropath Origins and Role
Astropaths (short for astro-telepath) serve throughout all the Imperium's divisions and make up a communication network designed to transmit and receive psychic messages through interstellar space.

They are chosen from the multitudes of psykers brought to Holy Terra on the Black Ships due to their great power. Once chosen, Astropaths receive psychic training by the Astra Telepathica's teaching division which is known as the Scholastia Psykana, before they are "soul bound" to the Emperor. This ritual transfers some of the Emperor's vast power to the psyker. Such an experience is traumatic for the psyker and not all survive or maintain their sanity. Even the survivors suffer damage to their physical senses, especially their eyes, so that almost all Astropaths are blind. Their increased psychic senses however tend to make up for this loss of sight.

Being joined with the Emperor is necessary however, as it greatly heightens Astropaths' already formidable powers, giving them the ability for which they were chosen - to transmit and receive psychic messages across large distances of space.

Due to the draining nature of their job many Astropaths are physically frail and can die quite young through exhaustion.

Imperial Guard
Although psychic mutation is frowned upon within the Imperium, certain mutants are recruited into use by the Imperial Guard as Sanctioned Psykers. These mutants may draw upon the power of the Warp, unleashing it upon their enemies. They are also called upon to advise high-ranking officers, with varying degrees of success. Their limited training and equipment leads to them being more easily preyed upon by the perils of the Warp than perhaps the much more powerful Librarians of the Space Marine Chapters. Each time they utilise their power, they put themselves at considerable risk and are prone to have their minds destroyed in the process. Some Psykers in rare cases have even literally exploded from overloading their bodies with Warp energy, taking out entire squads nearby. There is also the risk of possession or unintentionally channeling dangerous warp daemons, and for that reason, a Commisar is often present to quickly execute the Psyker before things go awry. That aside, they are still a potent force when deployed and used properly. On the battlefield, Sanctioned Psykers can advise an officer and guide their command, protect him from psychic attack, or fire bolts of lightning from their hands. Also The Imperial Guard, with the latest version of the tabletop game have begun using Psyker Battle Squads which are a larger group of lower ranking Sanctioned Psykers (typically between 5 and 10) that pool their powers together for each attack.

Outside of the tabletop game, Imperial Guard Sanctioned Psykers appear in the video game Dawn of War: Winter Assault as members of the Imperial Guard faction. They also appear within Dan Abnett's book, 'Only In Death,' as part of the Cadogus Fifty Second mechanised squadron.

Space Marines
Psykers are employed by the Space Marines in the form of Librarians. These individuals are chosen from among the most powerful and physically fit psykers. Librarians are responsible for maintaining the records of the Chapter they belong to, and can also use their talents to divide psychic mutants into those that are dangerous and those that can be utilised by the Imperium. Librarians, having much better equipment (Aegis hood circuitry, etc.), willpower, protection and training, combined with the enhancements of a Space Marine, are much less prone to the perils of the Warp than other Imperial psykers.

On the battlefield, Librarians are fearsome opponents, able to unleash devastating psychic powers and augment their own physical prowess. They are also skilled at defending themselves and their battle brothers from psychic attack.

The Inquisition
Though they are tasked with hunting down rogue psykers and collecting latent ones for training to aid the Imperium, many inquisitors are psykers themselves, though with the strength of will and psychic resilience to control their abilities. Inquisitor Gideon Ravenor is an especially potent example. Like much of their organization, one Inquisitor's psychic abilities can vary greatly from another's. Some specialise in unleashing torrents of fire while others, like Inquisitor Gregor Eisenhorn, specialise in powers that aid them in interrogations or to fool an enemy into stepping out from cover, dropping his weapon, or any number of other subtle 'mind tricks'.

Grey Knights
The Grey Knights Chapter of Space Marines is wholly made up of psykers: being a psyker is a condition for recruitment. This makes the already rigorous process of candidate selection even more so, to the point of causing all candidates to completely lose their memories of their lives before their selection. Surprisingly, despite being entirely composed of psykers, and thus uniquely vulnerable to the temptations of the Warp, there has never been a recorded instance of a Grey Knight falling to Chaos. This is attributed to the hyper-devout faith in the Emperor of Mankind possessed by all Grey Knights that is conditioned into them within the recruitment process into the Inquisition. Grey Knights are also the only Space Marine Chapter that is included within the Inquisition and as such receive even further processing in order to prevent corruption of the Inquisition as a whole. In the game, every Grey Knight unit or character may utilize individual powers (and some may use more than one per turn). Being a Psyker allows even a newly initiated Grey Knights to use a Nemesis Force Weapon, a powerful combat weapon with various, specialised forms. The Grey Knights also have access to many more specialised forms of wargear, usually unavailable to other forces, such as the Nemesis Dreadknight, a living behemoth of adamantium piloted by a single Grey Knight Terminator. In addition, much of their equipment and psychic potential has further, more potent effects if used on Daemons.

Witch Hunters
The Sisters of Battle, also known as the Witch Hunters, are sometimes known to bind psykers for use as a member of an inquisitorial retinue. Even though the primary purpose of the Ordo Hereticus is to hunt down and kill these rogue psykers an Inquisitor will sometimes have mercy for the truly repentant ones. As a means of atoning for their sins in the eyes of the Emperor, a bound psyker will serve as a means of protecting an inquisitor and their retinue from the effects of some psychic attacks. This service is considered to be a very rewarding act for the witch hunter because it is a means of saving their soul.

Eldar
Every Eldar has latent psychic ability. The most common manifestation of this seems to be their ability to speak telepathically with each other and sense emotions. Among all the races, the Eldar possess some of the most powerful psykers, using their ability to divine the future to shape their fate and also unleashing devastating powers on those that oppose them, however the sheer power they generate combined ensures that they must be cautious unless they attract the attention of Chaos and so are forced to become highly disciplined and regulated in psychic usage. Eldar Psykers come in the form of either Farseers or Warlocks, the former being the more powerful. Farseers will lead the Eldar warhost against the enemy and shape the course of battle with their powers. Warlocks are typically bodyguards and possess lesser, normally defensive powers. The Ulthwé Craftworld is said to possess the greatest number and the greatest quality of Eldar Psykers, due to its proximity to the Eye of Terror, and they can divine much further into the future and with better clarity than that of other Craftworlds. The Craftworld Iyanden has a variant of Warlocks, called Spiritseers. They differ very little from their normal counterparts. Spiritseers can guide Wraithguards in combat, better directing their awesome firepower for optimum efficiency. Harlequins, a sub-group of Eldar are frequently accompanied by Shadowseers, psykers who affect the emotions and create illusions.

Legions of Chaos
The forces of Chaos host a great many mutants among their number. Chaos psykers can perform various tasks such as summoning daemons and unleashing devastating powers upon the enemy. Most psykers amongst the forces of Chaos, especially among the Chaos Marine legions, are sorcerors. The Chaos God Tzeentch is devoted to sorcery; legions worshiping Tzeentch such as the Thousand Sons possess a large number of psykers that can aid in battle. Other legions such as the World Eaters denounce magic and psychic ability in favour of the wanton bloodshed of close combat and the Iron Warriors often sneer at sorcery. Chaos sorcerers can unleash potent powers and are fearsome individuals, but are often mutated beyond recognition. Tzeentch Sorcerers are especially potent with the art of dark magic

Orks
All Orks are relatively powerful latent psykers and are capable of pooling their psychic ability to enhance the ferocity of their attacks. However, they do have true, active psykers known as Weird Boyz. Ork psykers differ from those of the other races in that they don't draw their power from the Warp, but instead from the latent psychic powers that all Orks have. The Weird Boyz then channel this Waaagh! energy to inflict damage upon their foes, but often end up killing themselves in the process.

Necrons
The general belief is that Necrons do not have Psykers, as they are little more than robots, and are described as having virtually no souls; meanwhile, C'tan are described as considering warp energies to be "anathema". The Necrons also are notable for utilizing technology specifically designed for destroying psykers, specifically the "pariahs".

Tyranids
The alien race of the Tyranids is one of the most psychically active races in the galaxy, if not the most, with every single Tyranid telepathically connected to all others in what is called the Hive Mind. It is suspected that this constant and massive "psychic traffic" is what causes the Shadow of the Warp, a phenomenon that makes Warp travel and astropathy almost impossible near a large Tyranid fleet. Though the lesser creatures have no psychic abilities of their own, the larger Tyranid warriors act as focal points for the Hive Mind, capable of mind-controlling all lesser Tyranids around them. Zoanthropes, creatures supposedly evolved by combining tyranid DNA with DNA from other psychically active races like the Eldar, are extremely powerful psykers to the point that, with the passing of the years, their bodies have devolved into little more than a overly bloated head attached to an atrophied, fetus-like body incapable of even moving on its own power, therefore requiring the creature to use its psychic abilities to levitate across the battlefield. Hive Tyrants are also very powerful psykers, although not as much as Zoanthropes, and act as the core of the Hive Mind within the Tyranid swarms. Larger Tyranids, such as Dominatrixes and the mysterious Norn Queens, are also psykers of immense power, though the full extent of their abilities is a matter of speculation.

Tau
Tau have no known psykers. In the video game Warhammer 40,000: Fire Warrior, it is revealed that the Tau are naturally resistant to the mutating effects of Chaos, having almost no psychic presence in the Warp at all. However, this does not prevent the Tau Ethereal, Ko'Vash, being blasted apart by a burst of Chaos energy. It is rumoured that the Ethereals are capable of utilising Warp power, as it is suggested that this is how they are able to cause such loyalty in all of the Tau, although it was suggested in the Warhammer 40,000 book, Xenology, that the Ethereals have a large scent-based organ in their head that allows them to control other Tau through pheromones.

Psyker Levels
There are different grades regarding the power of a psyker:
 * Alpha Plus
 * Alpha
 * Beta
 * Gamma
 * Delta
 * Epsilon

This list continues all the way down the Greek alphabet.

The power the top four grades represents is immense. A high Delta level can read the minds of a good sized town simultaneously, or crush a man to death against a wall in seconds. High grade psykers are extremely powerful, and not to be taken lightly. Beta level is the highest a human can go and still be considered sane.

An Alpha Plus, however, is a being of grotesque power. They are described in the 4th edition Rulebook as being able to "turn a man inside-out with a glance", "snap a Battle Titan in half with a flick of the wrist", and "a muttered syllable can turn an army upon itself in a frenzy of bloodlust". They are capable of destroying entire worlds - sometimes unintentionally.

There is some controversy as to whether this description should be taken as an objective description of the Alpha Plus Level of psychic mastery, or if it is intended to be read as Imperial propaganda, and just being the exaggerated view of the generally anti-psychic authorities of the 40K world. In Dan Abnett's works, where the term first appeared, the Alpha Level psyker Esarhaddon (also the name of the King of Assyria between 681-669 BC) is powerful and able to control hundreds of Imperial citizens as puppets against the protagonists, but he is not described as being powerful enough to destroy a battle Titan, and is eventually subdued (Many works of fiction show that psykers seem to specialise in certain areas of psychic ability, so it is possible that Esarhaddon specialised in mind control or mental manipulation). Abnett's works (specifically the Eisenhorn trilogy) also refer to characters having a "PQ" rating. It is unknown how this relates to a psyker's power.

Nevertheless, few Alpha or Αlpha Plus psykers can be controlled safely, or even at all. Because more powerful psykers attract proportionally more interest from warp-bound daemons, many are driven insane, tainted by Chaos, or even become possessed (examples include the Apex Twins, who were responsible for murdering scores of Imperial Regiments). They are one of the biggest threats the Inquisition has to face, and are the reason that the Ordo Hereticus was formed. Most are executed, as the threat they pose is simply too great to deal with or control in any large degree.

An example of a Beta level psyker is Sergeant Agun Soric, an Imperial Guardsman from the Gaunt's Ghosts series of novels by Dan Abnett. He is able to detect blood poisoning in a fellow trooper, but his most prominent power is his ability to write messages to himself, which are contained in a brass message shell. Even after throwing the shell away, he would soon find it wriggling in his pocket, containing a message written in his own handwriting. At first the messages contained advice or warnings, but soon began to include criticism as he began to realize what he was, and the danger he posed as an untrained psyker. He is eventually discovered and taken by the Inquisition's Black Ships. His ultimate fate remained unknown for several novels until "Only In Death", where he is discovered by Commissar Viktor Hark, who shoots him to spare him the misery of living any more.

In Ian Watson's novel Space Marine, an individual's psychic profile is represented by a decimal value, presumably from 0 to 1, instead of using the Greek alphabet system.

Anti-Psyker Weaponry
Several types of anti-psyker weaponry have been developed by the Imperium, Necrons and other races to counter psykers. For the Imperium, these include the Culexus Assassin and their psykout weapons, which have devastating effects on psykers. Weapons include psycannon, warp swords, and other psykers. Necrons have developed several Pylons that, once complete will completely separate the warp from the material universe, thus rendering psykers useless. On a smaller scale there are the Pariahs, Necrons made from humans with the pariah gene - this makes them, like the Culexus assassins, soulless, and severely debilitating to nearby psykers.

The Greek Alphabet system of measuring psyker potential also applies to measuring anti-psykers. The lowest recorded example so far is an Omega Minus (the polar opposite of an Alpha Plus).

Untouchables are similar to Pariahs, but are widely assumed to have less of a blunting effect (although an accurate comparison has never been made). Untouchables cancel out psychic power cast near them or around them. Some even have the ability to consciously focus their power. It is also possible for an Untouchables power to be overwhelmed by a sufficiently strong psychic force. Alizabeth Bequin, an associate of Inquisitor Eisenhorn, was psychically overwhelmed by the warp sentience of an ancient Titan she was attempting to disable. Wystan Frauka, an untouchable in the service of Inquisitor Ravenor, was also made "touchable" due to unusual psychic activity.

Lastly, the Dark Eldar, while not having any known psykers among their ranks, have developed weapons designed for psyker destruction. One of the most gruesome (and rare) is the Crucible of Malediction, a nightmarish device which contains the essence of a slain psyker tortured into insanity. When the Dark Eldar use this weapon, the psykers tormented soul is released and its power has the potential to consume any psyker on the battlefield.

Notes and references
psyker psionici