When we got this guy our average level was about 58, lowest 55 highest 62. He was a 61 Wizard immune to stuns or mezzes, melee max was 670 on me, 450'ish on our tank. Doubles but doesn't quad that I saw, does enrage tho. He also gates at about 10% health...which can really suck. He is slowable.
Couple of things to note, we pulled him a total of 3x in 30 minutes (3 wipes) and he never ran out of mana....and he also gated each time. We really should have cleared the rest of his room, i suggest you do that too if you fight him and have everyone including your cleric ready to unload nukes on him at 10%.