Underrealm

A vast network of caves stretching beneath the surface of Sapience, the Underrealm (not to be confused with the Underworld) is the racial home of such creatures as hobgoblins, goblins, ogres, horkvals, and even the dreaded Tsol'teth. Known in the Tsol'teth tongue as "Anzari-tarin," which means "World of Darkness," the Underrealm has not been heard from in quite some time, and the Tsol'teth in particular have yet to be seen since the Dun Valley Saga.