Hive Fleet

A Hive Fleet is a large armada of living, biological starships created by the Tyranids for the purpose of gathering the raw materials and biomass necessary for the reproduction and expansion of their species. A Hive Fleet is used to attack and strip star systems of their biomass using the full range of Tyranid biomorphs. Only three full Tyranid Hive Fleets have ever come into direct contact with the Imperium of Man, but they have all brought devastating damage and loss of life. The Imperium's Segmentum Ultima Command designated them as: Hive Fleet Behemoth, Hive Fleet Kraken and Hive Fleet Leviathan, and they each first made contact with Imperial space in the Eastern Fringes of the galaxy, in the Segmentum Ultima. Hive Fleet Behemoth arrived in the Milky Way Galaxy in 745.M41, Hive Fleet Kraken in 993.M41 and Hive Fleet Leviathan in 997.M41. Each Hive Fleet is ultimately governed by the collective psychic Hive Mind of the Tyranid species, though at the heart of any Hive Fleet are the Norn-Queens who interpret the will of the Hive Mind for other Tyranid organisms and who personally birth almost every Tyranid biomorph present in the fleet, save for its Hive Ships. The potent psychic power of every Hive Fleet's connection to the Hive Mind produces a "Shadow in the Warp" that prevents travel or communication through the Warp in the astrographic vicinity of the Hive Fleet.

Primary Hive Fleets

 * Hive Fleet Behemoth  - Hive Fleet Behemoth was the first major Tyranid Hive Fleet encountered and defeated by the Imperium of Man. The ensuing conflict became known as the First Tyrannic War. The Hive Fleet was eventually destroyed in 745.M41 by the combined might of the Ultramarines, the White Scars, and the Imperial Navy.
 * Hive Fleet Kraken - Hive Fleet Kraken was the second major Tyranid Hive Fleet to invade the galaxy. It was responsible for the outbreak of the Second Tyrannic War, which began officially in 992.M41 and ended only after the Ultramarines Chapter of Space Marines successfully broke the back of the Tyranid invasion in Imperial space at the Battle of Ichar IV and the Eldar of Craftworld Iyanden successfully defended their home, at great cost, against the Tyranid horde.
 * Hive Fleet Leviathan - Hive Fleet Leviathan was the third and largest Tyranid incursion into the Milky Way Galaxy in 997.M41 and marked the start of the ongoing Third Tyrannic War for the Imperium of Mankind. Less than five standard years after the defeat of the Hive Fleet Kraken in the Second Tyrannic War, Lord Inquisitor Kryptman noted the tell-tale signs of yet another Tyranid invasion in 997.M41. He implemented the Kryptman Census, burning out dozens of Astropaths in the attempt to contact scores of worlds on every fringe of the Imperium. Slowly, the responses -- and lack of them -- formed a pattern, and the venerable Inquisitor was able to chart the course of the Tyranids' latest Hive Fleet to arrive in the galaxy. Codenamed "Leviathan", this time the Tyranids were approaching from below the galactic plane, attacking from two points spaced wide apart in the shape of a closing pair of jaws, cutting off large portions of the galaxy from Warp travel or astropathic communication. At a great cost in human life, a combined force of Planetary Defence Force troops, two regiments of the Imperial Guard, the Ultramarines and Mortifactors Chapters of Astartes, and a Deathwatch Kill-team under the command of Inquisitor Kryptman crushed the left "half" of the Leviathan on the world of Tarsis Ultra, destroying the Tyranids nearest to Terra, and reestablishing astropathic contact with the worlds between Leviathan's jaws. The Imperium had won its first victory in a war that had only begun.

Other Hive Fleets
There are many other Hive Fleets known to exist in the galaxy or to be approaching it from the vast void of intergalactic space. Several of these other Hive Fleets are splinter fleets of the original three to invade the galaxy and include:

[[Category:H]]
 * Hive Fleet Ouroboris - When Miriamulus the Elder, the then-Cardinal of Thracian Primaris recorded the history of the "Legion of Ouroboris" in the 36th Millennium, this account detailed attacks in the Helican Sector in an earlier age. The legion was described as consisting of "winged monsters" that descended from the heavens and stripped the countryside of all life, "vomited from the bellies of great beasts which clouded the stars with their numbers". An analysis of the Warlord-class Titan Mechanica Cranus, a cited veteran of the Ouroboris Wars, reveals distinctive bio-plasma scarring and pyro-acid burns consistent with Tyranid weapons. It is believed the Space Wolves Space Marine Chapter also possess trophies of Tyranid-like bio-forms dating from this epoch, including the so-called Kraken's Egg. The Cardinal attributes the Emperor himself with leading a crusade that caused the Beasts of Ouroboris to fall upon themselves, culminating in a mighty twelve day battle over a Warp rift dangerously close to the Eye of Terror. However, augur-dating techniques place the battle damage sustained by Mechanica Cranus as occurring post-Heresy, making the Emperor's embodied presence extremely unlikely. It is theorised that some Tyranids were drawn ahead of the other fleets by treacherous Warp currents and deposited at the Eye of Terror. This could explain the presence of Tryanid splinter fleets in Segmentums other than Tempestus.
 * Hive Fleet Tiamet - First encountered in the in the large double binary system on the Eastern Fringe known as the Tiamet System, it is theorised by Imperial Xenologists that this Hive Fleet was a Tyranid implant-probe, possibly molecular-coded DNA, sent ahead (perhaps cosmic debris or solar winds) to seed the system and spread of its own accord ahead of the arrival of much larger Hive Fleets. This system was discovered by an Imperial Explorator fleet hailing from Triplex Phall in the 35th Millennium. This system contained seven life-sustaining worlds and a host of lesser planetoids. The Explorator fleet discovered to their cost that every biosphere in the system was a Death World of the most voracious kind. Xenologists eventually determined that the life all over the system shared common ancestry and had developed various ways to get from world to world to seed new territory. Realising their own craft could be contaminated from entering the system by now, the Explorators quarantined themselves in Tiamet. They were to survive and report for another hundred and sixty two hours before succumbing to the lethal denizens of the fecund realm. Tiamtet was systematically fusion bombed on several occasions but life was never extinguished there; it now lies within the area swept over by Hive Fleet Kraken and as such its fate is unknown.
 * Hive Fleet Collossus - Several large nomadic fleets of curious, conch-like spacecraft apparently grown from stone were sighted through the Segmentum Tempestus and Ultima late in the 38th Millennium, bearing many similarities to Hive Fleets. The centauroid bio creatures aboard them were known to communicate, albeit telepathically, with other races -- unlike any other Tyranid organism before or since. The denizens of Colossus claimed to be slaves escaping their oppressors, but their frequent contacts with other alien races and attempts to settle in Imperium space cuased them to be declared Xenos Horribilis early in the 39th Millennium. The xenocidal fifty-year Zorastra-Attila wars followed as the entire race hurled itself against Humanity with terrifying ferocity, revealing their true, murderous nature. The last known Collossus vessel was eventually destroyed in 226.M39. The impact of its shattered remains rendered the northern hemisphere uninhabitable until late in the 41st Millennium. Only now are Explorator expeditions beginnings to piece together the truth. Due to inconsistent records, Imperial scholars cannot agree as to whether Collossus was wiped out during this campaign or during the Helican Crusade.
 * Hive Fleet Naga - Hive Fleet Naga was a relatively small Hive Fleet that invaded the galaxy from the Eastern Fringe somewhere to the galactic-north of the Tau Empire in 801.M41, destroying countless xenos domains and devouring several Eldar worlds. The Eldar referred to this Hive Fleet as Shai'naid, the Endlessly Winding Serpeent, and only through the combined efforts of Eldar fleets from Idharae, Iyanden and Malan'tai Craftworlds, was Hive Fleet Naga destroyed in 812.M41. Unfortunately, the Tyranid Hive Mind absorbed several dozen samples of new biomass, including the DNA of the Eldar, gaining valuable experience of Eldar military strategies and capabilities.
 * Hive Fleet Dagon - Hive Fleet Dagon, believed to be a splinter fleet of Hive Fleet Behemoth, was the first major Tyranid incursion into the Jericho Reach region of the Ultima Segmentum. The Shadow in the Warp cast by the Tyranid Hive Mind within this volatile region of space first heralded the arrival of this new and terrible Hive Fleet in 812.M41. Communication between parts of the Achilus Crusade and the re-conquered regions of the Jericho Reach was lost without warning. Particularly affected was the Orpheus Salient of the Crusade that was lost to communication and access with the rest of the Reach behind the Hive Fleet's crawling shadow of Warp interference. In 814.M41, the Deathwatch warship Thunder's Word entered the Freya System to investigate the silence of an Astropathic relay. It found no trace of the relay and indeed no trace of any life in the Freya System. Preparing to leave the system, the Thunder's Word encountered two Tyranid drone ships. Its hull scored and pitted with acid and its magazines nearly exhausted, the Thunder's Word arrived at Watch Fortress Erioch bringing news that the Tyranids had come to the Jericho Reach.
 * Hive Fleet Gorgon - A splinter fleet of Hive Fleet Behemoth that invaded the space of the Tau Empire in 899.M41, it represented the Tau's first horrific encounter with the Tyranids; the Hive Fleet was destroyed in 903.M41, through the combined efforts of the Tau Fire Caste and the Imperial Guard. Regions of the Tau Empire that have been left barren by the rampaging Hive Fleet are known as the Zone of Silence.
 * Hive Fleet Scarabus - Hive Fleet Scarabus was annihilated by the troops of the 9th Cadian Shock Troopers Regiment at the walls of Fortress Carcasson in 937.M41. The 9th Cadian did not lose even a single company of troops in this conflict.
 * Hive Fleet Locust - In 945.M41, this Hive Fleet largely wiped out the population of the Imperial world of Ulmore before the arrival of the Ultramarines Space Marine [[Chapter] in which the valiant Sons of Guilliman managed to drive back the hordes of the Great Devourer during the subsequent Battle of Ulmore.
 * Hive Fleet Perseus - This Tyranid Hive Fleet battle the Ultramarines Space Marine Chapter in 976.M41, but in 982.M41, it subsequently drifted out of Imperial held space and disappeared.
 * Hive Fleet Magalodon - Originally one of the splinter fleets that formed following the defeat of Hive Fleet Kraken in 992.M41, it has since grown exponentially large enough to be classified by the Imperium as a distinctive Hive Fleet of its own, which continues to ravage the Imperium.
 * Hive Fleet Jormungandr  - A small Tyranid Hive Fleet that entered the Imperium from the North East of the Ultima Segmentum in 993.M41, it quickly gathered large quantities of biomass by preying on unprotected worlds. Within two years of the first recorded attack, Jormungadr had effectively sealed off the entire Thalassi Sector. The Hive Fleet's vanguard was wiped out by Commander Chenkov leading over a million Imperial Guardsmen of the Valhallan Ice Warriors 18th "Tundra Wolves". When a portion of the Crimson Castellans Space Marine Chapter was corrupted by Chaos and turned Renegade, becoming a piratical warband of Chaos Space Marines, the Loyalist Castellans hunted down their corrupted brethren on the Hive World of Sephrax. But while they were engaged in battle, the Tyranid Hive Fleet Jormungandr unexpectedly descended upon the world and forced both sides to lay down their animosity against one another to try and defend themselves against the swarms of bloodthirsty Tyranids that threatened to destroy the world and both groups of Astartes. However, the Hive Fleet's sheer numbers soon overwhelmed all the combatants. The Crimson Castellans Chapter Master Sojai Antiro died in the bowels of the underhive of Hoventa Hive along side his 1st Company Veterans, growling his defiance with his last breath even as Tyranid Raveners encircled him and tore him to bloody shreds. The Renegade Crimson Castellans' leader, the pirate and self-styled "Arch-Commodore" Bloodspite, fled with the remainder of his forces to the lair he had established in an asteroid in orbit of Sephrax. But the asteroid and its defenders were ultimately swallowed by a Hive Ship of truly enormous size. The Crimson Castellans' Chapter homeworld of Vorl Secundus was abandoned shortly thereafter, and it is unknown whether any elements of the Chapter Loyalist or Renegade, may have survived the fury of Jormungandr.
 * Hive Fleet Medusa - This minor Hive Fleet invaded the galaxy from the galactic northeast through the are of the Ghoul Stars and close to the path of Hive Fleet Moloch in 997.M41. In 998.M41, Hive Fleet Medusa, mistakenly thought by the Imperium to be another tendril of Hive Fleet Leviathan, invaded the isolated Ice World of Shadrac. Space Marines of the Space Wolves Space Marine Chapter fought side by side with the battered survivors of the 10th Slovak Imperial Guard garrison, enacting a heavy toll in alien dead before they were forced to fleet the planet.
 * Hive Fleet Moloch - A minor Hive Fleet that plunged through the Ghoul Stars into the galactic north of the known galaxy in 998.M41. A vanguard tendril first threatened the Agri-World of Jollov in 932.M41 just as just as Techno Magus Stannum Vir discovered fragments of a lost Standard Template Construct (STC) on the planet. The world's spaceport was defended by [[Imperial Guard regiments comprised of Agathon, Catachan Jungle Fighters, Kanak, Molov, and Mordian Iron Guard regiments, selling themselves dearly, which bought enough time for the Adeptus Mechanicus to flee with their precious STC discovery. Much later, the 9th Vostroyan Firstborn Regiment, "The Old Irascibles" met their ultimate fate during the Fall of Karak Prime in 998.M41. They held the main hive city for 18 months against the brutal onslaught of a splinter fleet of Hive Fleet Moloch, valiantly facing a Tyranid swarm that stretched from the base of the city's walls to the distant horizon. With the onset of midwinter, and with the rapid depletion of ammunition and supplies, the 9th Vostroyan knew that they were doomed and vowed to sell their lives dearly. Only when the bulk of the Tyranid swarm had passed into the city did the regiment detonate its nucleonic stack, incinerating the hive, its defenders and an estimated 85% of the Tyranid swarm. With the coming of midwinter, the few surviving Tyranid organisms eventually starved to death and the splinter fleet was entirely defeated.
 * Hive Fleet Ophidia - First encountered in 998.M41, Hive Fleet Ophidia has apparently been mostly destroyed, though splinter fleets and remnants still remain active in the southern regions of the Ultima Segmentum.
 * Hive Fleet Hydra - This dormant Hive Fleet was recently discovered in 999.M41 by the Dark Eldar of the Poisoned Fang Kabal on the very extremes of the eastern spiral arm. Instead of destroying the vulnerable Hive Fleet, the Dark Eldar boarded the largest Hive vessels, intent on bringing new specimens back to their Kabal's Haemonculi. However, the Dark Eldar were unprepared for the rate at which the bio-ships awoke from their aeons-long hibernation, and every pirate that set foot inside one of the living ship was killed, butchered by a frenzied tide of Tyranids spawned to protect the ship. The remaining Dark Eldar fleet attempted to escape, but for every drone ship they destroyed, two more took its place. Prematurely awakened from its slumber, Hive Fleet Hydra accelerated its advance into the galaxy to slake its hunger.
 * Hive Fleet Charybidis & Hive Fleet Scylla - Hive Fleets Chraybdis and Scylla are separate Hive Fleets that are both carving parallel paths through the Segmentum Pacificus, the closest known Tyranid threat to Holy Terra. Unless the the Saim-Hann Eldar Craftworld alters its course it will fall into the clutches of the twin Hive fleets.
 * Hive Fleet Eumenides - Sometime during the late 41st Millennium, this Tyranid Hive Fleet battled against Hunter Cadres of the Tau Empire led by Commander Shadowsun.
 * Hive Fleet Grendel - One of many new Hive Fleets that have recently emerged from their cold sleep through the inter-galactic void, Hive Fleet Grendel currently assails the known galaxy.
 * Hive Fleet Harbinger - A recent Hive Fleet that currently assails the Imperium, a splinter fleet of Hive Fleet Harbinger recently consumed the Imperial Forge World of Arcetri.

Splinter Fleets
The scattered remnants of the great attack by Hive Fleet Kraken on Ichar IV fled towards the galactic core, eventually driving within the Imperial defensive perimeters that had been erected to contain the Kraken. These so-called Tyranid splinter fleets have in many ways become an even greater threat to the galaxy then the greater Hive Fleets from which they spawned, as they feed on unsuspecting and unprepared worlds that lie far from the primary warzone against the Tyranids. Running battles with the splinter fleets continued for many years after the Kraken was defeated, which drained Imperial defences when facing the much larger Tyranid incursions to come. It is doubtful if any full accounting of the true devastation wrought by these splinter fleets will ever be known.

Most splinter fleets comprise as few as a dozen Hive Ships. Yet even a dozen of these massive bioships are more than capable of overruning a life-bearing world and harvesting all of its biomass so that it can grow into an even larger and more dangerous threat. Some splinter fleets have become so large that the Imperium has classified then as a new, distinct Hive Fleet. An example of this process is the birth of Hive Fleet Magalodon which grew from one of the Kraken's tendrils and continues to ravage Imperial space.

There is no doubt that by this point the Tyranid Hive Mind has learned a great deal about the galaxy's defences from the actions of these splinter fleets. Every battle that a group of Tyranids engages in, whether they are victorious or not, only adds to the Hive Mind's growing depth of knowledge about its prey within the Milky Way Galaxy. Some Imperial savants of a particularly melancholic turn of mind believe that gaining this information was the true goal of Hive Fleet Kraken's invasion. It is perhaps preferable to believe that the Hive Mind has planned this outcome in advance, than to believe that it has the strategic skill to turn even its greatest defeats into longer-term victories.