Hydra takes its name from the myth of the beast that grew two heads for every one struck away, and no title could suit it better. A comparatively recent arrival, it drifts along in the wake of the great fleet Leviathan, hunting down the defeated remnants of earlier hive fleets and cannibalising them to absorb their genetic memory, growing ever richer in stolen adaptation as it comes.
Its sheer fecundity is its weapon. Every organism Hydra fields, down to the lowliest slimer maggot, breeds and multiplies at a horrifying rate, so that its swarms seem to have no bottom and no end. When it closes upon a world it first seeds the upper atmosphere with countless spore clusters, each cradling scores of dormant hormagaunts and termagants. As its vanguard broods meet resistance and begin to die, every slain creature looses a synaptic death-cry, and at that psychic signal the waiting spores burst open across the sky, disgorging fresh legions directly into the fighting.
Hydra was roused early from its long hibernation by Drukhari raiders who boarded its greatest bio-ships in search of specimens for the flesh-sculptors of Commorragh. They had gravely misjudged their quarry, for the ships woke faster than any pirate expected, and every raider who set foot within was torn apart. When the survivors turned to flee, they found that for every drone-ship they destroyed, two more rose to hound them. To wage war on Hydra is not to fight an army but to drown beneath one.
Tyranids
Order of battle
The Hive Fleet Hydra field the units of the Tyranids — a detachment from the roster:
Kindred formations
Other Tyranids formations
Hive Fleet BehemothThe first hive fleet to breach Imperial space, a brutal vanguard that taught humanity the true meaning of extinction.
Hive Fleet GorgonAn endlessly adaptive tendril whose bio-forms rewrite their own flesh mid-campaign, answering any weapon turned against them within a single generation.
Hive Fleet JormungandrA subterranean hive fleet that honeycombs whole worlds with tunnels and armours its bio-ships in asteroid rock, collapsing cities from below before the defenders know war has come.
Hive Fleet KrakenA fractured, unpredictable tide that scattered across a thousand worlds at once, proving no single line of defense could contain it.
Hive Fleet KronosThe Hive Mind's answer to Chaos, a fleet of suffocating psychic silence and merciless ranged bombardment that withers daemons and seals the wounds of the warp.
Hive Fleet LeviathanA colossal southern incursion whose sheer scale forced the Imperium to fight a two-front war of annihilation.