Well he has about 460 effective health and IIRC is susceptible to teleport. Pump some initiative then you can easily kill him in one turn with the good ol flesh-sacrifice + adrenaline rogue. I think I wrecked the deepdweller on the first turn with two rogues before he even moved. His damage doesn't mean much if he never gets to hit anyone. Chasing down the various skeletons scattered about is the actually annoying part.
Also, the fight is much easier if you initiate combat from the high ground. Don't walk into an ambush if you know it's there!
