In Doom RPG, the Lost Soul appears as a class of monster. There are three variations, identified by color:
* Phantom (green)
* Lost Soul (normal colors)
* Nightmare (blue)
Lost Souls can move three panels in a single turn instead of one, and will attack automatically once they are in an adjacent panel to the player, even if it has already moved. It attacks three times consecutively and can be damaged by the fire extinguisher.