The most overweight of evil minions within the Dungeon Keeper franchise, and also one of the hardiest, the Bile Demon is an exceedingly large and foul demon with a propensity for consuming large quantities of food. Sustenance is such a factor for the Bile Demon that they cannot be attracted at all if the player has any less than twenty-five Hatchery tiles, and their immense girth requires a Lair of at least the same size. Despite outward appearances of slothfulness, Bile Demons are more than happy to pitch in at a Workshop if there is room to accommodate them, and they can become quite hard to kill when fully trained. Due to their innate familiarity with vile odors, Bile Demons are completely immune to poison and gas attacks, and their size prevents them from being affected by Wind spells. Special care should be taken in dungeons which also house Skeletons, as these fleshless minions are inherently at odds with the fleshy Bile Demons.
Bile Demons seem to have no legs, or at least none that are visible beneath their sizable bellies. They move around primarily by shifting their weight from place to place with their lengthy arms. Two elongated horns also sprout from either side of their head, each of which is attached by chain to a spiked iron ball, allowing the Bile Demon to use its horns as improvised flails. They are also wont to wear large nose rings. Outside of melee attacks with their horns, Bile Demons are fond of using poisonous gas attacks in combat, which they are uniquely immune to. At higher levels, they also learn the ability to use grenades, although this skill can only be used by the player while possessing them.