Crav the General Nah is the Ruler of Rimbor, though the planet is currently divided by a holy war.
Crav is currently seeking objects of great power to help him both end the war on Rimbor and stop the coming “Great Darkness” that has been foreseen.
Crav’s son is Jo Nah aka Ultra Boy, a member of the Legion of Super-Heroes. Crav despises the Legion and considers Jo to be a traitor.