Bats are natural inhabitants of caves and other such dank places, so it is no surprise that they would also congregate near the gateways to Hell. Their exposure to the vile powers that emanate from the demons that frequent these dark places has tainted these bats with arcane powers. They have also acquired a taste for human flesh and fall upon unsuspecting travelers who stray too far from safe passageways. While a single Bat Demon is an annoyance, in swarms, they are lethal, swarming their foes and tearing off mouthfuls of flesh with their sharp teeth.