If Marcus is successful in kidnapping ISobel, the Last Light Inn falls and all npcs but Jaheira become undead, including Dammon. You have to kill them all then, again, including Dammon.
So.... you just have to rail down Marcus and cast Sanctuary to Isobel? Right?
Think people here got stuck on the part of the suggestion that matters the least.
Indeed, there are several ways Dammon can die, and you as player might not realize it/the consequences. The Marcus incident with Isobel is an instant ruining event, but also if you try to kill the Strange Ox things can turn badly very quickly too, and you might not even realize it’ll put Dammon at risk either.
The Marcus thing is worse since you might not even have noticed Dammon there, as OP said. I know it took me a few visits to Last Light and a wrong turn to find him the first time.
I think the solution here is to give OP the solution to kill marcus as fast as possible.
My suggestion:
Priest: Cast Sanctuary to Isobel.
