Has faced the party twice now.
First time, he was trying to finish a ritual involving the soul of ’Tasia. His allies tried to protect him while he finished the ritual, but to no avail.
The second time, he showed in the body of some random civilian and summoned a seed of hell fire that set fire to the pouring rain. His body was consumed by the hell fire, along with a few houses, a few innocent civilians, and all of the metal you could find quickly.