You made it to Whurnore and found that an undead prince wasn’t the only thing there. You were greeted by some creatures that were vaguely humanoid in shape, but made out of something like rock and with the facial features of something like a lobster. And, most importantly, they could pass through stone. They died, all the same. These tunnel thugs turned out to be led by a vampire that you were able to destroy after a lengthy battle. Sadly, though, it was obvious this vampire was not the undead duergar prince; it was a goblin.
It took some work, but you found the goblin’s treasure trove, high up in an alcove carved into a wall. You had to climb up to find it, but once there you found gold, and boots, and a wand.