Do you mean the Executioner's area accessible from the sewer? If so, I never managed to kill the executioner, so I can't really help with that beyond advising you look at the walkthrough here on GB.
I just looked through the walkthrough, it seems that the castle treasure room is inaccessible. Annoying to have treasure just out of your grasp, isn't it?
http://www.gamebanshee.com/divinediv...fistcastle.php
Here's the information on the Dragon items:
http://www.gamebanshee.com/divinediv...ragonarmor.php