Just fought him and he is an Enchanter (tash, dementia, but didn't notice him trying to charm).
Also he was yellow to 59 and blue to 61... so exactly level 60.
He gated at low health and healed up to around 35%, so try to fight at his spawn spot.
Talking of spawn spot. If you drop down the ladder, run to the corner with the undead spawn and look along the wall with the doorway, he is the second spawn past the door.
Dropped the ring, which despite all the criticism here was still an upgrade for the 61 enchanter in the group. 65 mana is quite nice when your int is capped.