Dark Dwarves

When the dark elves fled into the dark places of the earth at the end of the First Wars, they took many dwarven slaves with them. Over time, the harsh conditions of the Undersea as well as the cruelty of the dark elves and other denizens of the Undersea that kept dwarves as slaves changed them, until they became an entirely different, true breeding dwarven sub-race. They eventually rose up against their captors, and led by a great warrior named Duerili (not yet a god), they freed themselves and have made a place for themselves in the Undersea.

Dark dwarves, or duergar as they are sometimes known, are considered dwarves for the purposes of taking talents or other rules specific terms.