|Weapon Used||Large Claws and see below|
|Habitat||Demonic Planes, Mirrors|
A Mirror Demon takes the appearance of a humanoid, usually a female human, with four arms and four faces.
Mirror Demons summoned to the mortal plane always lurk in mirrors, usually as guardians. Whenever a creature passes by, the demon attempts to pull its victims through the mirrors toward the Demonic Planes from whence it comes; one single hit to its victim is all it requires to grab it and take it to its doom. 
However, the links which binds the demon to the mortal plane is quite tenuous. Shattering the mirror where it lurks causes the Demon itself to crack and shatter, thus severing whatever link the creature has made between worlds. Also, merely damaging the mirror seems to correspondingly damage the Demon.
- In depictions of the Mirror Demon, the monster is always shown with four faces - one on the front of its head, one on the top, and one on each side. In Siege of Sardath it is actually stated that the Mirror Demon has four "heads" (presumably meaning faces). If this is actually the case, and not just a description from the player's point of view, then the rear of a Mirror Demon's head is in fact faceless.
- Also in Siege of Sardath, a Mirror Demon is named as "Lix Tetrax".
- There are rudimentary special rules given for fighting Mirror Demons in the bestiary, Out of the Pit, however the fight with a Mirror Demon in the gamebook Night Dragon expands them, using skill tests to see whether the player is dragged through the mirror or not. However, since these rules apply to a situation in a dream sequence, their validity in actual combat situations is rather questionable.