|Habitat||Demonic Plane, Hills, Mountains|
Despite possessing stone-like properties, Rock Demons' bodies are well articulated and also vulnerable to being cut by blades. Their flesh apparently has a strange quality to it, flowing and bending - impossibly considering the solid substance it appears to be made of. The creature's humanoid form is also huge, thickset, and stands at over twelve feet.
Being a Demon, these physical advantages are not put to any good use. The creature is notoriously stupid and belligerent, taking great pleasure in pulverising anything it encounters. It's well equipped for this activity - the Out of the Pit bestiary states that the Demon's fists are the size of a Storm Giant's head.
Some scholars speculate that Rock Demons are the creations of the Demon Princes, made as a debased parody of Earth Elementals. There is obviously some passing similarity, but Rock Demons are nowhere near as formidable as Earth Elementals, who are physically far stronger, and can, by virtue of their elemental nature, move stone and earth. 
- A Rock Demon is the only Demon in Out of the Pit to have its intelligence unflatteringly described as "none".