Duergar (Dungeons & Dragons)

In the Dungeons & Dragons fantasy role-playing game the duergar are a race of cruel and evil dwarves. They can be thought of as the dwarvish equivalent of the drow. The duergar alternate between working in concert with the drow and being at odds with them, as the drow believe themselves superior even to the duergar. Duergar are stoic and hard-working, toiling under the gaze of Laduguer, their strict and unforgiving deity, in order to create wealth. They have a deep-seated grudge against other dwarven races, due to their exile from their midst and legends stating that the rest of dwarvenkind abandoned the duergar to mind flayer rule thousands of years ago.

The name comes from the duergar of norse mythology, who were the builders of Gleipnir.

Settings and sources
Duergar have the ability to become invisible in the Forgotten Realms setting, where they dwell in the Underdark in cities such as Gracklstugh. In the Dragonlance campaign setting, they are called daergar. The Expanded Psionics Handbook updates them to be a naturally psionic race, with the psi-like abilities to turn invisible and expand in size once per day.