I know he went off and left after getting ressurected in the adventure, "The return of the Eight", but I don't really know anything ABOUT him, other than he's a powerful wizard that was once an ally of Mordenkainen... what is his alignment and level? Thank you...
Planescape, Dungeons & Dragons, their logos, Wizards of the Coast, and the Wizards of the Coast logo are ©2008, Wizards of the Coast, a subsidiary of Hasbro Inc. and used with permission.
He's lawful good. Here's some unofficial stats.
Tenser was Ernie Gygax's PC in Gary Gygax's original Greyhawk campaign. He belonged to the Citadel of Eight, which was Mordenkainen's adventuring group. After the Citadel of Eight broke up, Tenser joined Mordenkainen's coven of wizards, the Circle of Eight, in 474 CY. He was murdered by his fellow Circle of Eight member Rary later on, along with all of the clones that he was known to have in storage. One last clone had been captured by the nalfeshnee wizard Tuerny, however (and transformed rather humiliatingly into a blue dretch), and adventurers rescued it in 586 or so, when he was returned to his true form. Tenser by that time had grown disgusted with the amoral nature of Mordenkainen's group and did not rejoin the group, retiring to his fortress beneath the Nyr Dyv to work unambiguously for the forces of good.
What else about him? He's in his 60s by now. He always dresses in blue. He is polite, quick-witted, and gregarious. He has an extensive intelligence network and many alliances with nonhuman creatures such as jann, firbolgs, centaurs, swanmays, and fey.