I even got him down to 1HP using Living on the Edge. Nothing.
EDIT:
After repeatedly getting him down to nothing the demon began ping ponging around possessing all my people recklessly using consumables. Also the dwarf I freed from the demon bounced back and forth from hostile to friendly. Often attacking members of my party who were NOT possessed.
Frustrating quest. But finally finished it.
Last edited by BoogieMan; 03/10/17 02:50 AM.