Omega
From Mistipedia
Known only as "Omega," this spellcaster was presumed to be long-dead by Perseyus Lathenna. Omega's spellbooks were discovered on the Isle of Demise and eventually forwarded to Lathenna.
Omega is described as a sorcerer, but the fact that he possessed spellbooks makes his actual character class uncertain.
References
Van Richten's Arsenal, p. 33