In reality, Iuz was trapped under Castle Greyhawk by the Lord Mayor of Greyhawk, Zagyg Yragerne in the Mad Archmage's own quest for godhood. Many of the orcs, clans that had served him for years, as well as some of his human followers claimed he has ascended to full godhood, beginning to worship him, and actually able to perform cleric spells based on their worship. It was about this time Iuz used a dark ritual to steal power and life force from many victims, making himself a demigod. They claimed he had an army of evil men, terrible wizards and savage orcs, and worst of all, fiends. They told tales of Iuz being the son of a demon and a necromancer, being a 7ft tall demon driven by destruction. Refugees from his conquests told tales of a road of skulls leading from the hills to the capital of the land, Dorakaa. In less than three years, that territory was expanded, creating a small kingdom. By the end of his first year on the throne Iuz had assimilated the three surrounding fiefs. In 479 CY, a warlord in the Howling Hills left control of his land to his 'son'. He is considered the enemy of every sane and free person in the Flanaess and every religion, except his own and holds a particular hatred for Zagyg, Vecna and St. He is referred to as 'The Old One' or Iuz the Evil, and worshiped as the God of Deceit, Pain, Oppression and Evil. His weapon of choice is the whip and greatsword. Originally described as very handsome, Iuz now appears either as an old man with poisonous spit, or a big, red, hulking demon like creature.

Iuz is the half-fiend or cambion demigod son of Graz'zt, a demon lord of the Abyss, and the human witch Iggwilv.

5e demigod