In the World of Greyhawk campaign setting for the Dungeons & Dragons roleplaying game, Iuz is the chaotic evil demigod of Deceit, Pain, Oppression, and Evil. Iuz is variously called "The Old One" and "Old Wicked," among other aliases. Unlike most Greyhawk deities, Iuz makes his home on Oerth, where he rules a broad swath of the Flanaess known as the Empire of Iuz.