Gruumsh is the chaotic evil god of destruction, and the lord of marauding hordes, though some are known to worship him as a war god. While Bane's followers conquer, Gruumsh's slaughter, representing the carnage of war. He is known as the One-Eyed God, supposedly due to losing his left eye in a battle against Corellon (although many of his worshippers claim that he was born with only one eye, and did not in fact lose it in battle). For this reason, his most devout followers, orcs, possess a lingering hatred for elves and eladrin. Many orc priests wear eye patches to show their devotion to Gruumsh.
The followers of Gruumsh are told to conquer and destroy, crush the weak, breed and let their numbers flourish, and let nothing stand in their way.
Gruumsh makes his lair in Chernoggar, where his forces clash with Bane's in an endless cycle of death and violence, all in the One-Eyed God's attempt to become the only war god in existence.