The Khyber Cults

A loose scattering of minor cults, dark worship and local practices, these cults give praise to the forces beneath the earth, in particular the fiendish Overlords and their servants, believed to be the spawn of Khyber, the Dragon Below. While the Dark Six are considered hostile and opposed to civilization, they are still creations of Siberys and Eberron, part of how the world and the mortals in it function together. The Overlords are creatures of destruction and fear, spawned by Khyber in opposition to the rest of creation.
These cults look to the Overlords out of fear, desire for power, or madness and corruption, and have no organization or alliance to each other. Others even turn to the Daelkyr, aberrant forces of madness and unreality created by Xoriat, the Far Realm. In general, they follow destructive and irrational beliefs that cannot co-exist with society as a whole, and tend to self-destruct, hopefully before doing too much harm.