Iuz (EYE-ooze) is thought to be the half-fiend son of the demon lord Graz'zt and the powerful Sorceror Queen Iggwilv. Iuz became one of the early Suzerain’s of the World Emperor. He oversaw several provinces in the southern part of the Empire. He made his palace in the heart of Elfskeep, an old city built by the Dark Elves before the Uttermost War. Here evil and wickedness grew in his heart. Iuz somehow found a way to make himself nearly immortal and obtain power and divine accession. Iuz then summoned forth fiends and demons and made a try for the Empire. Unfortunately for Iuz his attempt at domination came at the same time as the first of the Great Slave Raids. To the Dark Elves it made no difference if they raided the World Emperor or Iuz. Since that time Iuz has sat on his Throne of Bone and slowly accumulated power and territory  Iuz appears as a shriveled old man or as huge, demonic-looking being, Iuz has many fiendish allies and impersonates other powers to fool mortals and increase his territory. His symbol is a grinning skull, and he holds a particular hatred for Zagny, Vecna, St. Cuthbert, and the City State of the World Emperor.

The weak must be exploited, tortured, and stripped of hope. The strong must be constantly wary of betrayal by their underlings. Pain is power, and inflicting pain demonstrates power best. Crush those beneath you. Iuz must be obeyed, and those who defy him will know absolute pain.

Iuz’s church is cruel, barbaric, and sadistic. The clerics revel in cruelty and inflicting fear on those weaker than themselves, and they forever try to outdo each other. The more exalted members of their ranks who become part of the Boneheart (three echelons of six members, though not all are clerics) keep quiet in Iuz’s presence unless commanded to speak. Senior clerics become token rulers in the provinces that Iuz dominates, although Iuz holds them responsible for events therein, so this is a mixed blessing. Iuz is served directly by the Boneheart - two tiers (Greater and Lesser) of six advisors each (clerics and wizards), and by the Boneshadow, six spies and evildoers who roam the world.

Iuz’s clerics have an affinity for calling and controlling fiends and demons. Trophy hunting is also important to Iuz’s clerics, and a fine array of stuffed and mounted heads brings approval and esteem. Possession of a true work of art (e.g. an embalmed and stuffed paladin) gains considerable kudos for the owner. The clerics of Iuz create spells and magic items of terrible power and evil nature, and travel the world to commit acts of evil and to search out Iuz's enemies.