Shadowkith

The Shadowkith are a race of purple mutant cannibals from planet Grace within the Koronus Expanse in Warhammer 40,000. Descendants of exiled Imperial nobles, Crime Lords, and the slaves of both, their existence is due to the effects of both a Warp Storm stopping the Rogue Trader who founded Grace from resupplying the world with food, and the storm's affects on the bodies and psyches of the trapped locals as food supplies dwindled. The Shadowkith now lure in unsuspecting ships with distress calls to devour their crew.