[JR Jansen]

It's supposed to happen, allthough the ghast doesn't appear and kills Imoen. It's Imoen who turns into a ghast. This has to do with the demons gaze attack. He can use this once a round (or was it turn, don't know exactly) but he can hold your people. Afterwards, they get another icon on their portrait. If you look at the character sheet that icon will be ID'ed as the 'dying' icon. The only way to get rid of it is to use dispel magic. So have your mages AND/OR clerics AND/OR druids memorize it and, just to be safe, keep a few scrolls aswell. After you dispelled it, it should be gone and you should be safe. Remember to do it quickly or the affected party member will turn into a ghast. Took me a long time to figure this out myself.