Screamers of Tzeentch

Screamers are the sky-sharks of Tzeentch, daemonic predators shaped like the great rays that once glided through Terra's vanished oceans. They swim with equal ease through open air, the airless void and the tides of the Immaterium, and many scholars believe it is raw warp-energy, not wind, that bears them aloft. As they wheel and dive they trail contrails of glittering, many-hued sparks and give voice to the piercing, high-pitched whine that earns them their name.

A Screamer hunts from above, folding its wings to plunge upon its prey in a shriek of warp-lightning before slashing through flesh and armour with curved tusks. Whatever survives the first pass is snatched up in its jaws, to be devoured on the wing or carried aloft and dropped to shatter far below. Nor are the beasts confined to the battlefield: Screamers can scent the weak points in a voidship's Geller field and tear their way through, spilling into the corridors within to slaughter crews trapped in the dark. Wherever they gather, the very air seems to scream, and the wise know to flee the coming of the shoals.