Valsuvius
Human archmage native to the island now called Itrefaulk who flourished @ 3000 BCY and was one of the founders of the wizard's guild which eventually became The Citadel of High Magic. Legends say he was of near god-like power, but disappeared after going insane due to a great tragedy.
In the year CY 1123 a group of adventurers called The Defenders of the Flame discovered the magical mental prison that Valsuvius had been stuck in and freed him. They all returned to the Citadel. He has since disappeared again.