Rheddrian was the mortal identity used by the immortal Benekander, based on his previous alien existence, but we didn't realize it at the time. He usually sent us on various missions.

He acted similar to a 36th level magic-user in this guise, but seeing as he was really an immortal, he could actually do pretty much anything he darn well felt like.
(As long as the more powerful immortals didn't catch him doing it, and he was a sneaky guy.)