I farmed him last night (~14 hours ago) and having killed his cronies off, and sending the henchies to the next horizon, I was suprised to find that he will cast only +-3 spells and then stop and do nothing making for an easy kill.
He drops:
Exuro's Will - Staff
Energy +10
Fire Dmg: 11-22 (req. 9 Fire Magic)
Halves skill recharge of spells (Chance: 20%)
Energy +5 (While Health is above 50%)
Health +60
Two-handed
You can find him due south of the Gates of Madness exit into Domain of Secrets.
Another guildie and I each got the drop within 10 tries
