In Dwarf mythology, caves and passages under the influence of shadow magic are referred to as "black wells." In addition to their latent power, many feature portals or other links to the Shadowfell. Dwarves who seek out the power of a black well are typically desperate, mad, or both.
Dwarf communities banish or even execute clan members who turn to shadow magic, which they fear as a corrupting, evil force. Shadow magic's promises of power can spread through a stronghold like a disease, but arc said to yield only weakness and ruin. For this reason, dwarves who embrace shadow magic turn their backs on their people, living among humans and other races.
Although a few dwarves learn to channel shadow magic on their own, those who master the power of the Shadowfell do so as members of an order known as the Obsidian Cave. Those in the order arc typically outcasts, accused of heinous crimes and banished from Dwarven society. Nonetheless, they wage a hidden war against the enemies of their people in the darkness of the world below.
Would-be members of the cabal must venture into the Shadowfell to the borders of the realm of the dead. There, they seek an isolated crag of black rock where the masters of the order dwell. This mountain, known as the Ebon Spire, is said to appear and disappear according to the strange currents of shadow magic that surround it. Legends say that only an exiled Dwarf bereft of hope and determined to die in the service of the Dwarven people can find this place.
A newcomer to the Ebon Spire faces a series of tests designed to ensure loyalty to the order and to the Dwarven race. Such acolytes might be forced to endure days of unremitting hardship and torment. Other tests might send the initiate out into the world, tasked with slaying or spying on a known enemy of the Dwarves. Only after surviving such tests is a Dwarf initiated into the order-and given the full secrets of shadow magic.
Dwarves of the Obsidian Cave rarely deal with other Dwarves, preferring instead to wage a singular war against Orcs, Drow, and other threats to their people. When Dwarves of the Order die, their souls return to the Ebon Spire, where they linger as spiteful undead spirits. For initiates of the Obsidian Cave, destroying the spirit of a fallen master serves as a final test of one's dedication.