Trolls

Trolls are mountain-dwelling creatures with a hard, grey hide that resembles rocks. They live in mines and caves, and presumably eat meat (mostly dwarves and goblins, based off fossil evidence), although it is hard to find up in the Lonely Mountains. They are slow but big, and can be dangerous. They are often mistaken for dumb down in the lower mountains, but that is because their IQ is directly related to how cold it is. Ice trolls, also called yetis, are in fact credit with inventing basic algebra, among other things. They worship Gm'a, god of rocks. In troll mythology, he hatched out of a stone egg and the shards of the egg created the world. Some other shards created the moon.