Regeneration Is A Standard, Cheesy DM Trick
Okay Marivhon, you leap down and do some damage. Yes, the ghoulmaster is AC:5, but just so everyone knows, you need magic weapons to do damage. I think that's not a problem as everyone has stuff now, except maybe for Tut.
Moth, damage dealt. The ghoulmaster grunts in pain and decides to take it out on Dave FoO's face.
On a WI check, you'll notice that the ghoulmaster is regenerating!