Rimeskull is a mountain on the western edge of the Kodar Mountains in northwestern Varisia.1 Located on the banks of Lake Stormunder, it is named for the vaguely skull-shaped carving visible from miles away, the mouth of which is a large cave entrance.
The carving is a relic of ancient Thassilon, and the person depicted in the massive carving is the founder of Thassilon itself: Emperor Xin. During the time of this ancient empire, runelords commonly carved their faces into the mountainsides that faced their capital cities. The carving of Xin, however, faces the Runeforge, a place of great importance shared by all of the runelords.2
At the mountain's western base, just off the lake, lies a ring of seven ten-foot-tall, open-mouthed stone heads angled toward each other known as the Sihedron Circle. This Thassilonian ruin was recently discovered to be a magical entrance to the Runeforge.2