A prison that contains various nasty creatures either locked up or free to roam. This dungeon has various locked doors and chests which can be opened with keys found within. However, everything that is unlocked with the keys can also be picked open, but there are sections that cannot be accessed with just the keys alone. When found and used in the correct order the keys will eventually lead you to the Bandit Shield (See Bandit Shield Quest).
It would also appear that Oswald the assassin was once here to steal the shield for himself (See Silver Key).