Skarbrand is a Bloodthirster of Khorne.
Official Canon Edit
Skarbrand had once been Khorne's highest bloodthirster, until Tzeentch tricked him into becoming so angry and violent that he attempted to kill his own master. Khorne destroyed Skarbrand's wings and knocked him so hard that he lost any reason he once had. He continues to fight indiscriminately, though he also has an aura that causes everyone else around him to become just a violent as him.
TTS Canon Edit
Skarbrand was the victim of a ding-dong-ditch prank by Fyodor Karamazov. Too angry to move or do anything about it, he simply stood in the doorway and yelled.