The Rock Demon, the largest known coreling, wanders for the most up in the mountains, looking for easy prey, but sometimes it comes down to the lowlands to try to find a meal there. It has a large tail and is covered in stone armor. The biggest Rock demons are in the lowlands, they can`t hunt in the mountains because the snow hinders them. Rock demons can reach a height of 20 feet. There smaller cousins called stone demons which appear in the third book The Daylight War.
None known/ revealed in the first two books
Note: Arlen Bales, however, managed to sever a rock demons arm using protective wards.