Tyranids



The Tyranids are a fictional race from the Warhammer 40000 tabletop game and its spin-off media. They are known to the Imperium generally as Tyranids, because Tyran is the first known planet they devoured and where they were first encountered.

They are a nomadic alien race comprising many genetically engineered forms (see Tyranid genetics) created from harvested bio-mass. They are known as the "Great Devourer" and also "Shadow In The Warp" and pose a severe threat to the Imperium. They seek to consume all in their path, draining all planets of every resource.

Tyranids were first described in Rick Priestley's Rogue Trader, the first edition of the Warhammer 40,000. At that time they were not an emphasized race in the game, instead representing a limited number of occasionally-encountered alien antagonists. In later editions the Tyranids became a major race, popularized by a number of successful board games. Unlike most Warhammer 40,000 races, the Tyranids do not have a Warhammer Fantasy Battle counterpart. They are comparable in terms of their motivation and in some cases, motivating the appearance of the Zerg in the StarCraft series. They are also very similar to the Flood from the video game series Halo.

Tyranids are typically a fast, close-combat army that rely on overwhelming their enemies through superior numbers. They may also be bio-morphed to rely heavily on ranged combat, or field an impressive but small array of monstrous titans rather than a typical swarm. Tyranid armies are therefore able to bring a varied threat to bear on their opponents.

History
The hive fleets so far introduced by Games Workshop include Hive Fleet Behemoth, Hive Fleet Kraken, and Hive Fleet Leviathan. It is noted that these names are those ascribed to the Tyranid incursions by the scholars of the Imperium, rather than the Tyranid civilization themselves. There is no evidence shown in the fiction that Tyranids have language or civilization as understood by the protagonist civilizations native to the Milky Way. In many stories they communicate with a complex array of insectile clicking and buzzing noises, as well as reptilian war cries, growls and hisses.

Hive Fleet Behemoth invaded in a giant swarm of over a thousand ships, and reached as far into Imperium as Macragge, the home world of the Ultramarines, before it was destroyed. Hive Fleet Kraken had divided itself into a large number of sub-fleets, of which two major groups were eventually halted at the Battle of Iyanden and the Battle of Ichar IV. Surviving vessels spread out throughout the galaxy, forming splinter fleets. Hive Fleet Leviathan was made of two massive "jaws" approaching from below the galactic plane, spreading the phenomenon known as the Shadow in the Warp, which disrupts travel and communication within a given area.

Genestealers are the principal antagonist in the setting of the game Space Hulk, and short pieces of fiction frequently describe human encounters with Genestealers from the point of view of individuals such as Inquisitors. It is theorized in the Third Edition codex that Genestealers are a Tyranid/Human mutation, while Zoanthropes are a Tyranid/Eldar mutation and Biovores are a Tyranid/Ork mutation.

It has also been hinted, in the latest edition of the codex, that the Milky Way has been visited by Tyranids before. The Catachan Devil (a carnivorous arthropod found on the death world of Catachan) is suggested to be an evolutionary offshoot of the Ravener. Others, such as the Brainleaf, might also have similar connections. In addition, it is revealed in Ian Watson's Space Marine that the Tyranid Hive Mind was drawn to the Milky Way by the birth of the Chaos Gods, this "disturbance in the warp" was a signal of a multitude of advanced life to be harvested.

Very few planets manage to fend off a Tyranid invasion without resorting to Exterminatus, wiping out all life on the world. Those that do spend years on "mop up" work of rooting out the last surviving Tyranids.

Other Hive Fleets
Although the Space Marine codex background fiction states that Hive Fleet Behemoth was the first Hive fleet encountered by the Imperium, other background fiction, dated earlier (within the fictional universe's dating system) tells of encounters with creatures having some similarities to the Tyranids (Horus Rising, for example, though this is widely disputed due to the Megarachnids physical traits that differ greatly from any known Tyranid life form).


 * Hive Fleet Locust: White Dwarf issue 98 gives detailed information of the leaders of the Ultramarines chapter, and makes mention of a hive fleet called 'Locust', which the Ultramarines appear to have fought before Behemoth.


 * Hive Fleet Tiamat: Tiamat was named after a double binary system discovered in the 35th Millennium that contained an unusual seven planets, all later found to be death worlds. It was determined by Xenologists working for the Adeptus Mechanicus that all life in the system had a common genetic source. The Explorators decided to quarantine themselves on the planet after realizing their ships may have become contaminated by the time they spent in the system. The planet was later lost after the arrival of Hive Fleet Kraken, so Tiamat's ultimate fate remains unknown.


 * Hive Fleet Ouroboros: Cardinal Miriamulus the Elder, of the planet Thracian Primaris, recorded a Chaos-like invasion. Upon further examination of the enemy strategy, equipment used during the battle and trophies collected, it was determined that it was, indeed, a Tyranid invasion. Initial accounts credited the Hive Fleet's defeat to the Emperor himself; however, later analysis of artifacts recovered from the battle confirmed they dated after the Horus Heresy. It was theorized the Hive Fleet mistakenly strayed too close to the Eye of Terror and were left warped and mutated by exposure to its Chaotic energies.


 * Hive Fleet Colossus: In the 38th Millennium, several large nomadic fleets of conch-like vessels were sighted in Segmentum Tempestus and Ultima, bearing similarities to Tyranid Hive Fleets. The centauroid creatures aboard were known to communicate telepathically with other races-a trait not seen in other Tyranid lifeforms. The creatures claimed to be escaping their oppressors, but contact with other races and attempts to settle in Imperial territory resulted in them being declared as Xenos Horribillis early in the 39 millennium. The xenocidal fifty year Zorastra-Attila wars followed as the entire race fought Humanity with terrifying ferocity, revealing their true, violent nature. The last known Colossus vessel was destroyed by orbital defenses over Zorastra. Explorator are only now beginning to piece together the truth...


 * Hive Fleet Moloch: Hive Fleet Moloch is included in a map in the Warhammer 40,000 rulebook background section


 * Hive Fleet Jormungandr: Hive Fleet Jormungandr is also included in a map in the Warhammer 40,000 rulebook background section. In White Dwarf issue 227, Phil Kelly fields a Tyranid army in the issue's battle report, named Hive Fleet Jormungandr. Phil's army is painted in dark blues, some purple, and black.


 * Hive Fleet Hydra: Included in a map in the Warhammer 40,000 rulebook background section and also described in the 5th edition codex, Hydra was awoken from dormancy by Dark Eldar pirates who had thought to collect samples for their own purposes. Stirred by the intrusion, the Tyranids of Hydra slaughtered the Dark Eldar, then proceeded to advance on the galaxy at large.


 * Hive Fleet Scarabus: In the Imperial Guard codex there is an art work showing the carnage at fortress Carcasson showing the 9th Cadian battling what is presumed to be Hive Fleet Scarabus.


 * Hive Fleet Harbinger: In the Warhammer 40,000 rulebook on the Tyranid page, there is a color scheme for a Harbinger, which bears generally dark red carapace and chitin, and blue turquoise flesh.


 * Hive fleet Apophis: A less known Hive Fleet which has black carapace, red flesh, yellow lines on the carapace, green blood, eyes and tongues. Many other color schemes are shown online.


 * Hive Fleet Naga: Described in the 5th edition codex, Naga ravaged much of the Eldar's dwindling territories before it was finally wiped out.


 * Hive Fleet Gorgon: As described in the 5th edition codex, Gorgon assaulted many of the Tau Empire's holdings, which resulted in a frenzied conflict as the Tyranids of Gorgon evolved at an unparalleled rate to combat Tau weaponry and tactics. Unfortunately, Gorgon's fast adapting proved its downfall, as it swiftly ran out of resources to support the creation of new forces. The Hive Fleet was eventually destroyed by an alliance of Tau and Imperial forces, though three Hive ships did manage to escape.


 * Hive Fleet Medusa: Mistakenly thought by the Imperium to be part of Hive Fleet Leviathan, Medusa has invaded the isolated ice-world of Shadrac. Space Marines of the Space Wolf chapter battled side by side with the Imperial Guard, enacting a heavy toll in alien dead before they are forced to flee the planet.

The Hive Mind
Particularly learned protagonist characters in the background (generally Imperial human, but occasionally Eldar or Tau) are seen to refer to a controlling mechanism intrinsic to the Tyranid race, called the Hive Mind. The Hive Mind is the gestalt metaphysical entity thought to emanate from and exert cohesive control over all Tyranid individuals through psychic manipulation. In terms of the terrestrial Tyranids' encounters with other species, generally in conflict, the Hive Mind is explained as filling the roles of social hierarchy, linguistic communication and military command and control as used by other races.

The Hive Mind's presence is delivered through "Synapse" creatures such as the Tyranid Dominatrix, Trygon Prime, Tyranid Prime, Hive Tyrant, Warrior, Zoanthrope, Brood Lord, and the dreaded Swarm Lord. Their presence makes all Tyranids in range immune to psychological assaults. Tyranids out of Synapse range will revert to their natural instincts and charge the closest enemy or retreat to the closest available cover. The Hive Mind is also represented in the tabletop games by various rules specific to players fielding Tyranids, and has a dramatic influence on the playing style of a Tyranid army. The presence of the Hive Mind is what separates Tyranids as an invading force able to devour worlds from stray Tyranids that act like animals and inhabit Death Worlds, such as the "Catachan Devil". Killing the synapse creatures causes severe tactical problems for a Tyranid army.

As a thematic device, the Hive Mind is also shown as being responsible for widespread (light-year scale) disruption of Imperial communications and superluminal travel via a mechanism known as the Shadow in the Warp. This introduces complications to the affairs of Imperial protagonists in fiction featuring Tyranids, as the human characters find themselves isolated from outside aid via warp travel and doomed to face the Tyranid menace alone.

The following quote, describing both the Tyranid synaptic hierarchy and the lurking presence of the Hive Mind within the consciousness of each individual Tyranid, can be attributed to Chief Librarian Tigurius following his psychic contact with the Hive Mind: "As I looked into its dead black eyes, I saw the terrible sentience it had in place of a soul. Behind that was the steel will of its leader. Further still I could feel its primogenitor coldly assessing me from the void. And looking back from the furthest recesses of the alien's mind... I can only describe it as an immortal hunger. It is this we cannot kill.".

Species and Biology


The Tyranids are all of a basic genetic stock, characterized by six limbs, both an endoskeleton and an exoskeleton, external skeletal features distinct from an internal skull, carapace plates on their head and a series of spiracles on their heads and at the base of their tails. These traits have led some players to call the Tyranids "bugs".

What follows is a list of the major Tyranid genera. Starting with the Codex: Tyranids published during the 3rd edition of Warhammer 40,000 and continuing to the current iteration, players are encouraged to create their own varying forms of the Tyranids. The player has the option of fielding a basic Tyranid (or a squad, which is called a "brood"); then the player is given a list of allowed upgrades which they are permitted to apply to the creature(s). Certain combinations of upgrades are frequently given nicknames to differentiate them from other versions of that creature - for example, a Carnifex outfitted with multiple guns may be called a "dakkafex" (amusingly, after the Ork references to ammunition being "Dakka"); a brood of Gaunts upgraded to carry short-ranged spike-firing weapons known as 'spinefists' may be called "Spinegaunts". The most mutable of the Tyranids are the Carnifex, the Hive Tyrant, the Warrior, and the Genestealer.

Synapse Creatures
Lower, less evolved breeds of Tyranid are constantly kept in check by the more advanced synapse creatures which have much stronger links to the Hive Mind. Killing a synapse creature will disorient all other Tyranids around it until another synapse creature arrives. In theory, if all synapse creatures are killed the lesser Tyranids will attack each other (this is only theory as a wipe out of synapse creatures has only occurred along with the destruction of the entire Tyranid army). The synapse creatures, which have the strongest link to the Hive Mind, include:


 * Norn Queen:Though not seen within the game as there is no model, within the 40k universe the Norn Queen resides in the hive ships and births all the various Tyranids. 'She' has the ability to manipulate them at the genetic level, therefore rapidly evolving new species to combat anti-Tyranid tactics.
 * Dominatrix: An army level supreme commander seen only at the Epic level. The Dominatrix model was made only for Epic, although one gamer made a 40K-scale one, which was featured in the Citadel Journal.
 * Hive Tyrant: A very large, very powerful and an extremely aggressive creature with access to many upgrades. Arguably one of the versitle Synapse Creatures commonly seen on the battlefield.
 * Tyranid Warrior: Superficially similar to Hive Tyrants, but are smaller and more numerous.
 * Broodlord: A larger, more powerful version of a Genestealer; similar to the Genestealer Patriarch described in the Second Edition background material. It is said that the Broodlord is the first genestealer of its brood to make land on a planet, hence, only one may be present per brood. (no longer a synapse creature in the 5th edition codex)
 * Trygon Prime: a variation of the Trygon species.

Large Tyranids
There are many other monstrous creatures that, while large, do not have the synaptic powers like the Hive Tyrant. They are all sub-sects of the Tyranid Warrior Genus. They include:


 * Lictor : Camouflaged scouts, closely related to Tyranid Warriors. They have the ability to leap out of hiding at enemy troops, making them difficult to counter (they also appear to have the ability to work completely independently of synaptic contact as they often operate deep behind enemy lines).
 * Carnifex: A large, tank-like creature, bred to spearhead assaults and/or provide fire support. The carnifex has more variations than any other unit in the Tyranid arsenal, making it extremely versatile. It is one of the strongest units in the army.
 * Ravener: Fast-moving, snake-like creatures capable of burrowing underground.
 * Tyrant Guard: Tyrant Guard act as large, durable living shields for the Hive Tyrant. The Tyrant Guard are born without eyes, and can only see when near the Hive Tyrant itself. It was suggested in 3rd Edition they were engineered from Space Marine DNA, giving rise to the extreme resilience and armor not otherwise possible except in the very largest creatures. Some have also are equipped with talons for a set of "lash-whips", living tentacular whips with barbed spines on their ends.
 * Hive Guard:The Hive Guard are charged with protecting Tyranid structures and are capable of unleashing salvo after salvo of intense firepower. They are heavily armored and have a body designed to be a stable firing platform for the massive impaler cannon bonded to their forelimbs.

Notable Tyranids
While the Tyranids are a Hive Mind entity and "recycle" their forces after each successful assault upon a planet, there have been occasional sightings of extraordinary individual creatures within the Tyranid armies. It is possible that these unique mutations have a genetic regeneration trait and that it would be the same organism arising after laying dormant for many years or that the organism is a recessive genetic mutation that recurs periodically. As the Tyranids never communicate with non-Tyranids, it is impossible to know whether these are actual individuals within the Tyranid community, or are new species that are slowly being introduced into the forces of the Hive Mind, but the latter is more likely.

Despite their apparent infamy, they are no more individuals than other Tyranids are, they simply are rarer and significantly more powerful (in both intelligence and strength) "prototype paragons" of their parent genuses: the Carnifex, Ravener, Lictor and Hive Tyrant, respectively. The Red Terror and Old One Eye also pioneered some of the newer biomorphs and weaponry, but the prototype versions they employ act somewhat differently than those later made available to their parent genuses, along with some abilities unique to them. All three of them have unique models with varying degrees of in-store availability as of early 2007; notable is that the Death Leaper was originally a conversion of an ordinary Lictor, before it was "mainstreamed" into its own model. The Swarmlord, the Doom of Malan'tai, the Parasite of Mortrex and the Ymgarl Genestealers were all released with the 5th edition Tyranid Codex in 2010.


 * Old One Eye: A monstrous Carnifex mutation with gigantic pincers and a missing eye. The creature was found on Macragge centuries after Hive Fleet Behemoth was destroyed. Originally presumed dead, Old One Eye was found by a band of smugglers, who planned to sell the carcass for a bounty. Unfortunately, the Carnifex revived inside the ship transporting its body: bereft of the Hive Mind's control and driven only by the urge to kill, Old One Eye then slaughtered the smugglers, ripped the ship apart and escaped to freedom. Notoriously hard to kill, it had the ability to rapidly regenerate even grievous wounds (to the point of completely resurrecting after a mortal wound), which led some to speculate that it was a genetic experiment of the Hive Mind. Something of interest to note is that it failed to regenerate the aforementioned lost eye, the scar burned down to the bone. It is believed Old One Eye was eventually found and reassimilated by the Tyranids, as some new Carnifexes have shown signs of this regenerative adaptation.


 * The Red Terror: A devastating powerful and aggressive mutation of the Ravener genus first sighted on the mining world of Devlan. It was speculated that there may be more than one Red Terror, as with all of the Tyranid notable "characters", but any engagements there may have been with other such creatures yielded no survivors. It was often well beloved by Tyranid players for its ability to swallow most kinds of opponents whole, preventing any cunning way of staying alive they can think of. In the impending new Tyranid Codex, a new creature, referred to as a 'Mawloc' will be included in the army. One of the Mawloc's most notable characteristics will be its ability to swallow victims whole, suggesting it is an evolution of the Red Terror.


 * Death Leaper: A particularly vicious Lictor introduced during the Cadian Rise of the Swarm campaign. It was originally encountered by a Space Marine named Brother Erasmus. The two fought and both were wounded, Brother Erasmus losing an eye and an arm. As a result of the damage sustained in this battle, Death Leaper's chitinous exoskeleton provides him less protection than most Lictors, but Death Leaper's stealth is unsurpassed, and it is able to conceal itself in places where normal Lictors would be unable to hide. A fourth edition "Death Leaper" was also heavily involved in the summer 2006 campaign, Medusa V, but is identical to the Rise of the Swarm Death Leaper in name only, and acts simply as a "special edition" version of the Lictor model if the supplemental rules for it are not used. The latest (fifth edition) Deathleaper has been given its own official entry in the codex as a special character, and is mainly focused on psychological warfare as well as the ability to appear and disappear at will.


 * Swarmlord: The evolutionary pinnacle of the Hive Tyrant genus, the Swarmlord combines the trademark ferocity of the Tyranids with a tactical acumen and intelligence acquired over centuries of conflict. This knowledge is achieved because every time the Swarmlord perishes on the battlefield, the Hive Mind reabsorbs its consciousness through the synaptic web, where its consciousness can be implanted into a new body: the Swarmlord is, to all intents and purposes, immortal. The Hive Mind's decision to reincarnate the Swarmlord appears to be a stress-induced response when it encounters an enemy that can't be overcome by physical and biological adaptation alone. The Swarmlord's intellect has brought death and destruction across the galaxy under different Hive Fleets and across in-game history.


 * Doom of Malan'tai: The Doom of Malan'tai refers both to a creature who destroyed an Eldar Craftworld almost single-handed, and to the destruction itself (the Eldar view the two as one and the same). After the climactic battle with Hive Fleet Naga near the Craftworld of Malan'tai, a single fatally wounded bio-vessel managed to come within range of the Craftworld and launch several mycetic spores at the Craftworld before it perished. As the Eldar focused on what they perceived to be the greater threats (Carnifexes, Venomthropes and Genestealers), a single creature went unnoticed as it quietly began feeding on the Craftworld's Infinty Circuit. Since this unique adaptation of the Zoanthrope genus fed on life energy and souls instead of flesh and blood, it was superbly adapted to dealing with the highly psychic Eldar. When the Eldar finally became aware of the true threat in the form of the vampiric leech feeding on their very lifeforce, it was too late as, having drained the Infinity Circuit dry, the Doom of Malan'tai was now unstoppable and had become able to pulverize Eldar forces with the merest extension of its mind; before long the entire craftworld was wiped out. Only a handful of Eldar survived the destruction of Malan'tai, and, when the Craftworld was found several years later, it was cold and lifeless with no sign of its destroyer.


 * Parasite of Mortrex: When the forces of Hive Fleet Kraken invaded the fortress world of Mortrex, the Tyranids were beaten back by the formidable defenses on the planet for ten days. However, on the tenth day of the invasion, the Imperial Guard encountered a new form of Tyranid: a winged creature the size of a Tyranid Warrior. The unidentified monster dove among the defenses, lashing out with strikes of its barbed tail. Those struck by the barb survived for a few seconds before they were torn apart from the inside out by dozens of Rippers: the creature's barb had implanted them inside the bodies of its victims. A handful of survivors made it back to the planet's Imperial fortresses, bearing word of this terrifying new threat which they dubbed the 'Parasite of Mortrex'. Time and time again, the Parasite attacked, and with every victim it claimed, the number of Rippers swarming over the planet's surface increased. Before long, only armored units could venture outside the fortresses in relative safety, and it didn't take long for the Tyranids to overcome this: the Parasite would use its diamond-hard mandibles to rip open the hulls of tanks, leaving the helpless crews to be ripped to shreds by the swarms of Rippers that poured in. Within two weeks, Mortrex was overrun: the only thing left of the planet was a final transmission warning of the Parasite. Though the Parasite has not been seen since, it has gained a terrifying reputation throughout the Imperium..


 * Ymgarl Genestealers: Initially thought to be animals native to the moons of the planet Ymgarl, these creatures were identified as Tyranid organisms not long after the end of the First Tyrannic War. The Ymgarl Genestealers are unique in that they are able to alter and evolve their bodies in a matter of seconds to serve their needs for defense or combat, unlike other Tyranids who must acquire new adaptations over several generations: however, the adaptability of the Ymgarl Genestealers comes at the price of an exceptionally high metabolism that can only be sated by gorging on the lifeblood of their prey. The Ymgarl Genestealers are also unique in that they are not created by a particular Hive Fleet, and are more likely the last remnant of a long-lost or destroyed fleet. They constantly seek out the Hive Mind, as though desperate to be reassimilated, traveling to worlds that lie in the path of a Hive Fleet's advance and aiding their Tyranid kin. However, the Hive Mind has no wish to reabsorb their biomass, likely because their unstable mutations would prove a liability, and after the Hive Fleet has consumed the world and moved on, the Ymgarl Genestealers are abandoned and left in hibernation. Unfortunately, they don't have to wait for long, for many come to investigate after a Tyranid attack, seeking information, survivors or riches among the ruins. More often than not, these leave with an altogether more lethal cargo in the holds of their ships, and the Ymgarl Genestealers continue their desperate pursuit of the Hive Mind.

Tyranid Titans
Tyranids also utilize creatures collectively known as bio-titans. For the 28 mm game player, most of these are only available as special order resin models, while the Trygon and Mawloc have been available as plastic kits from January 16, 2010; some metal miniatures are available for the Epic system. The Titans include:


 * Malanthrope: The Malanthrope resembles a very large Zoanthrope fused with a lictor. They are psychic.
 * Tervigon: A Tervigon is a powerful creature that carries broods of dormant Termagants inside its abdomen. In battle, the Tervigon can awaken and release the Tyranids inside it to join the attack.
 * Tyrannofex: Protected by an almost-impenetrable carapace and armed with formidable short-range weaponry, a Tyrannofex is a very powerful unit.
 * Trygon: The Trygon resembles a very large version of a Ravener. It attacks with huge scything claws and bio-electrical pulses created within its body.
 * Mawloc: Mawlocs are huge worm-like creatures with massive razor-toothed maws that act as the entryway to their equally cavernous gullets.
 * Hierodule: The Hierodule resembles a very large Carnifex; comes in both scythed (Combat) and barbed (Shooting) variants.
 * Hierophant: The Hierophant is a massive, spider-like creature. One of the most powerful and largest bio-titans.
 * Harridan: The Harridan resembles a very large Gargoyle. Used to transport Gargoyles over long distances.
 * Dominatrix: The Dominatrix is a specialized Bio-Titan, commanding the forces on the battlefield and providing the highest level of psychic control. They are said to be the female counterpart to the Hive Tyrant.
 * Norn Queens, as described in the novel Warriors of Ultramar, fill the role of the "queen" of the hive, similar to that of a queen ant.

The Gaunts
The Gaunt genus encompasses the basic units of a Tyranid invasion force. They are man-sized or smaller, come in waves, and are totally expendable. Gaunts are also a mutable genus, with over 400 documented variations; some of the common sorts are:


 * Hormagaunt: fast-moving assault species with scything talons.
 * Termagaunt: similar to Hormagaunts, but with ranged weaponry. These are used as the "foot soldiers" for the Tyranids and are the most common type of gaunt.
 * Spinegaunt: a Termagant variant armed with spinefist weapon-symbiotes.
 * Deathgaunt / Devilgaunt: Another variant gaunt with a devourer.
 * Gargoyle: Winged Termagants, with atrophied legs and the ability to spit plasma at short range.

Other Tyranids
The most unusual forms of Tyranid are those which may have incorporated the DNA of races assimilated during conquest. Examples include:


 * Genestealer: Genestealers are much-feared assault specialists, capable of scouting and infiltrating the target of the main Tyranid army. Genestealers also infest space hulks with the aid of their hybrid offspring, who prepare special incubation chambers for their purestrain kin. When the space hulk in question is visited by looters or individuals legitimately looking for salvage, the purestrains are released, infecting the unfortunate explorers with Tyranid DNA. The first genestealers were contacted on the moons of Ymgarl, 200 years before Tyran: they were thought to be native organisms, and only after the defeat of Hive Fleet Behemoth was it discovered they were Tyranid organisms. This would suggest that the hive mind has been aware of humans long before the present threat.
 * Zoanthrope: Zoanthropes exhibit psychic abilities. On occasion they have been shown to possess a synaptic link to the Hive Mind. The 3rd Edition Codex hinted that they were constructed using some Eldar DNA (hence their emphasis on psychic powers).
 * Venomthrope: The Venomthrope's whip-like tentacles drip with a multitude of alien poisons. Under a Venomthrope's heavy carapace is a network of bulging, gas filled bladders that emit yellowish spore clouds. These clouds are lethal to non-Tyranid organisms and dense enough to obscure nearby Tyranid organisms.
 * Biovore: Biovores act as artillery for the Tyranids by firing Spore Mines at enemies. They resemble nothing more than large, bipedal bears (albeit "tyranidized") with large cannons growing from their backs. In 3rd Edition it was hinted they were engineered from Orks.
 * Spore Mines are seen quite often when battling against Tyranid swarms of many sizes. They can sometimes come from creatures with a biomorphic weapon known as "Spore Cysts", but more often seen fired from barrels of the tyranid artillery units known as Biovores. In 4th Edition there were several varieties of spore mines; Frag Spores, which explode in a manner not unlike a frag grenade, Toxin Spores, which damage enemies with a cloud of various neurotoxins, and Bio-Acid Spores, which are very effective in penetrating vehicle armor (and everything else). However, as of 5th edition the selection has been simplified to just Frag Spores. 5th Edition also allowed spore mine to be dropped from space at the beginning of the game using deepstrike rules.
 * Pyrovore: A Pyrovore's maw drips with corrosive acids that are powerful enough to reduce armor, flesh and bone to a gooey, smoldering mucous. When confronted by a foe the Pyrovore launches forth an incandescent fireball from its dorsal bio-weapon that reduces its victim to a pile of burning ash. Its two front legs are fused together and has a sixth toe with a big scythe on the end to slash or impale enemy units from close range.
 * Ripper Swarms Rippers are small, snake-like Tyranids are generally only seen in large swarms which traverse the planet during the final stages of an invasion, ingesting all that they can in order to speed along the ultimate consumption of all usable material on the planet. Energetic and persistent, they can pull down and consume creatures many times their own size. They act independently, but can be caught in the area of a leader-beast's Synapse effect to be put to use in battle. It is speculated that Rippers are a larval form of Tyranid. Eventually, the rippers will become bloated full of biomass, unfit for combat. At this point, they simply enter into the reclamation pools and get melted down for reuse.
 * Mycetic spores are organic transport devices used by the Tyranids to deploy seeding swarms in the initial stages of their planetary invasion, similar to the drop pods used by Imperial forces. They are released into the target planet's atmosphere from Tyranid hive ships in orbit, using various methods to slow down their descent enough for the Tyranid organisms inside to survive the resulting impact.
 * Sky-Slasher Swarms are simply a winged version of the standard ripper strain. They are used to swarm sky-bound opponents when other airborne Tyranid lifeforms prove unable to defeat the foe.

Discontinued Tyranids
The following creatures were part of the Tyranid forces in the very first edition, but were dropped completely afterwards. They also represent outside races that were "controlled" by Tyranids.


 * Squigs: Small Ork DNA-based creatures that were quickly replaced by the more Tyranid-like Ripper Swarms. Originally introduced as the result of Tyranids meddling with Ork DNA, later they were retconned to being closely related to Orkoids. They are still used in various ways by the Orks and form the basics for an Ork economy. In-game they are represented in many ways and sizes, from massive squiggoths, to attack pets used by Ork bosses, to the suicidal bomm squigs strapped with explosives and sent by Ork Tankbustas to chase enemy vehicles.


 * Zoat: Mysterious reptilian, centaur-like alien species enslaved by the Hive Mind. The Zoats' telepathic powers were used to communicate with other species, a task the Hive Mind eventually deemed futile. The Zoat made its only published appearance in Ian Watson's novel Space Marine, in which a single Zoat tried to stall an Imperial Fist invasion of a Tyranid Hiveship. The Zoat was killed, but not before killing several Fists on its own. According to Games Workshop, Zoats are now officially extinct, having been destroyed in their entirety by the human Imperium.

Behavior
Some fans find the anonymity of the Tyranids appealing: being a psychic collective, individuality is irrelevant to the Hive Mind, and Tyranid armies behave accordingly. Many Tyranid weapon systems, such as Spore Mines, are sacrificial in nature, and the Tyranids have been known to expend lesser organisms for strategic purposes as casually as human beings expend ammunition.

Tyranids are noted and feared in the game's literature and canon for being without number, without fear, and without mercy. The following quote is taken from a doomed Imperial psyker, found on the back of the Fourth Edition Codex: "They are coming! I feel them scratching inside my mind, scratching, screaming, running, so many - so, so many voices. They are coming for us - flesh body and soul!"

The Tyranids are notable for being one of the greatest threats to the Imperium - on par with the forces of Chaos. Whenever the Hive Mind dispatches a Hive Fleet, thousands of worlds are consumed and destroyed. The Tyranids are usually beaten back at great cost (an outcome akin to that of the Battle of Macragge) or, that failing, they manage to surmount innumerable casualties and overwhelm the defenders of the planets they assail (Gryphonne IV and Thandros being two examples thereof). This pattern could change as shown by the Stark Report, an in-game report released by the Strategic Collective (a secret Imperial research group created five months after the defeat of Hive Fleet Leviathan in order to discover Tyranid weaknesses and future invasion points). The Stark Report suggests that the previous three Tyranid Hive Fleets (Kraken, Leviathan, and Behemoth) were but fractions of a far larger whole, and that an appropriate response would be an unprecedented 500% increase in Imperial mobilization rates. This does not take into account forces needed to keep other foes such as the Orks and Chaos Space Marines in check.

Early Board Game Incarnations
Genestealers were introduced in the 1980s with Space Hulk, and later featured in Space Crusade, along with the short-lived Genestealer Magus. The first recognizable incarnation of Tyranid warriors appeared in Advanced Space Crusade in 1990, featuring biological weaponry such as boneswords and deathspitters.

First Edition, Rogue Trader
Tyranids were first mentioned under the heading Tyranids and the Hive Fleets, and were illustrated in a form not too different from that of Gaunts.

The first Tyranids used conventional, non-biological equipment such as lasguns and flak armor (although the rulebook stated that these represented organic equipment with similar capabilities). The principal unit available to the Tyranids was the Zoat, a centaur-like creature enslaved to fight on the behalf of their Tyranid masters.

Second Edition
Second Edition Warhammer 40,000, released in 1993, featured the Tyranids in the supplemental books Wargear and Codex Imperialis, and then later in their own devoted army Codex. An extensive model range was released, representing most of the units described in these publications. The army was, however, very different from the factions previously seen in the game.

The Tyranid player now had access to a range of unit types roughly equivalent to that of the other factions, including the Hive Tyrant, Termagants, Hormagaunts, the main adversary in Space Hulk Genestealers, Gargoyles previously seen in Epic 40,000, Tyranid Warriors, the Carnifex, Zoanthropes (a Tyranid psyker in addition to the Hive Tyrant), Lictors, and the Biovore.

Third/Fourth Edition
The Tyranid supplement to Third Edition Warhammer 40,000, like most of the other supplements released at that time, focused on revamping the rules for the various units while maintaining the overall structure of the army, so that veteran players would not find their older collections unusable or less useful in the new edition. It did however add some new units and tweak the behavior of others. A brand new model range, somewhat different from the older ones, was released to coincide with the new publication. New units included: the Tyrant Guard and Raveners.

The Third Edition Codex, as with a number of subsequent publications, included an army list which allowed far greater flexibility to the player than previous army lists, allowing extensive customization of units; at the time more so than any other available faction. Unit types noted as a 'Mutable Genus' in the main army list were permitted to be extensively modified by choosing from numerous options in the 'Custom Hive Fleet' section of the book. The options available bore a resemblance to the random equipment tables featured in Rogue Trader, but were no longer randomized.

The nature of the army list in Third Edition further cemented the Tyranid army's reputation for fielding vast numbers of models, allowing the player to overwhelm an opponent with weight of numbers. This was even more pronounced in the variant Seeding Swarm army list published in White Dwarf and later in Chapter Approved, which represented the initial stages of a massive Tyranid assault and even further emphasized the use of many expendable, 'cannon-fodder' type units. One of the more overlooked abilities is the new "without numbers" rule, which allowed for literally an unlimited number of gaunts in a single game, emphasizing the "cannon-fodder" trait of the Tyranids.

The release of the fourth edition codex added a new model range, new rules, and new units, most notably the Broodlord, and revamped units such as the Carnifex. This new codex also enables Tyranid players to field a grand total of eight large Tyranids to be fielded in a 1500 point battle, although the player would still have to field compulsory troops choices. With this concept Tyranid armies can now boast either the many troops and/or a just few powerful units.

Fifth Edition
A new Tyranid codex was released on January 16, 2010, written by Robin Cruddace. It included 15 new species of Tyranid, and legendary heroes like the Swarmlord, Old One Eye and the Doom of Malan'tai. In addition, some models saw a point cost reduction, which allowed certain Tyranid armies to field more units, though, notably, this was not the case for all Tyranid units, as several saw point increases in this edition.

Tyranids in Alternative Games
The Tyranids are represented in three of the Specialist Games produced by Games Workshop: Battlefleet: Gothic, Epic, and Inquisitor.

In Battlefleet: Gothic, a game focusing on spaceship to spaceship combat, they are represented by four models that represent the massive ships of the Tyranid Hivefleet. In Epic, the game of large scale combat using smaller miniatures, they are represented by a combination of Titans and standard Tyranid troops. In Inquisitor, the narrative skirmish game using Warhammer 40,000 type characters, the Tyranids are represented by the Genestealer and Hybrid models under the generic roleplaying category of "aliens." They are individual members of the Genestealer Cults who work towards espionage and propagating their species in secret to weaken a planet's defenses before an invasion, as opposed to being part of the Hivefleet army that seeks to swarm over all in their path and consume them.

Tyranids in Video Games
Warhammer 40,000: Dawn of War II currently includes Tyranids as a playable race along with the Eldar, Orks, and Space Marines. The playable heroes include the Ravener Alpha, Lictor Alpha, and a Hive Tyrant, and the Tyranids act as the primary enemy in the single player campaign. Also, the Tyranids are one of the few Warhammer 40000 factions that were not in the original game, Warhammer 40000: Dawn of War, although an unofficial modification has been produced that adds them as a playable race. The fact that Tyranids were not officially present is likely due to their nature; as Tyranids do not create structures or technology in the same way as the other races (not to mention the lack of usable wargear because of this), it would be difficult to have them perform as the other races do in the game. Relic has also repeatedly stated that they wanted to include the Tyranids in Dawn Of War, but the game's graphic engine "wouldn't do them justice". Other issues cited included significant differences in economy.