Fiend, from Ultima VII Part Two
Formerly the wizard, Shal, the Fiend is an evil human who has been completely consumed by raw Chaos. He makes his home in the caves surrounding Serpent's Fang, and is utterly insane.
The Avatar encountered the Fiend during the quest for the Silver Seed, as he had within his lair one of the four Orbs required to gain access to the chamber where the Seed was kept. The Ring of Reagents was created by Shal with the aid of the Serpent of Chaos at the cost of Shal ‘losing himself’ to pure chaos and becoming the creature known as the Fiend.
The Avatar has the option to deny returning the ring to the Fiend, which will cause him to attack.