Undead is the group term used for Skeletons, Vampires and Ghosts in Dungeon Keeper.
Undead creatures are unique in the fact that they are all immune to Poison Gas.
Dungeon Keeper 2
The only undead creatures in Dungeon Keeper 2 are Skeletons and Vampires. Aside from their immunities, another feature of these creatures is the fact that they never get knocked unconscious, and therefore cannot be imprisoned or converted. It also means that one should be very careful when trying to train them in a Combat Pit. Skeletons simply shatter when they run out of health, and Vampires either disintegrate into a cloud of bats (if they are level 1 or defeated by a Monk), or resurrect one level lower in a Graveyard.
