The Tyranid hive fleets are rapacious alien swarms that flow from beyond the galactic fringe to devour all life. From their chitinous blades and parasitic guns to the vast hive ships that ferry them across the stars, everything about the Tyranids is organic. Like an endless insect swarm, their individual warrior organisms are given unified purpose by the imperatives of a vast and ineffable alien consciousness known as the Hive Mind.

This vast, ineffable, and predatory metasentience has but a single goal – to feed. Its fleets strip world after world of all biomass, leaving nothing in their wake. The smothering psychic shroud known as the Shadow in the Warp rolls before them, isolating each new prey world and sowing terror through its defenders before the invasion swarms descend.

When the Tyranids attack they do so in unstoppable numbers, unleashing nightmarish bio-weapons upon their victims.