Grimbal

A typical ghost can stray only a short distance from where it was killed or the place it haunts. A typical limit is 120 feet. Some ghosts are instead bound to a room, building, item, or creature that was special to it rather than a location.

Restoring Grimbal's head from area F4 to his remains in this room allows him to move on to the afterlife.

When Grimbal damages a living creature with his ghostly hand Strike, the ghost gains 5 temporary Hit Points, and the creature must succeed at a DC 24 will save or become Stupefied 1. Further damage dealt by the ghost increases this stupefied value by 1 on a failed save to a maximum of Stupefied 4. Each time a creature affected by drain mind gets a full night's rest, decrease its stupefied value caused by drain mind by 1.