Lords of the Deep Dark
The Deep Dark is a underground world of caverns, tunnels and crevases. Very few of its inhabitants are even aware that a surface world exists as it is months of travel to the surface. There is a long history of empires and kingdoms controlling large parts of the Deep Dark. Currently no political faction is strong enough or organized enough to control all of the Deep Dark. It contains thousands of square miles of rock and openings, most of which is unmapped and unexplored by all but its local inhabitants.