Historical primary Orc god. In the year II:1929, Gruumsh fought the Dark Mage (with help from Hades) to a standstill. This angered Gruumsh so much that he diverted a large meteor to strike the mage's castle. The resulting explosion created the Dark Bay, effectively snuffed out all existing civilizations, and ended the second age.
As punishment for this crime, the other gods imprisoned Gruumsh in a massive pyramid on “prison plane 121” (see Voyager #60-66).
In III:1131, Gruumsh was freed from his prison by The Boondock Saints in an attempt to bring about the end of “The King in Yellow”. In the process, Gruumsh was killed by a Chaos Beast.