Duergar

, also known as gray dwarves, were a subterranean race. They carved out an existence in the Underdark, often near volcanoes.Their kinship to other dwarven subraces could be compared to that of the drow to surface elves.

Description
Like their other dwarves, duergar were typically stocky figures, though beyond this there were many differences. Both male and female duergar were typically bald, with females also lacking the capacity to grow facial hair. Many were also thinner than their dwarven brethren. Most obvious, however, was their dull gray skin and hair, often matched with an equally stolid expression. Because many duergar found on the surface world were criminal exiles, a surface dweller who encountered one of the gray dwarves was likely to notice facial and arm tattoos that marked the duergar as a traitor to his or her people

Abilities
Duergar were in some ways even better adapted to underground living than other dwarves. While other dwarves lacked the capacity to see completely in the deepest darkness, this was not a problem for duergar. Duergar were also immune to many of the ancient techniques used by the mind flayers to control them, such as paralysis, phantasms, alchemical poisons, or some types of illusion.

Personality
Duergar were at heart a grim and bitter race, pessimistic of their future and deeply cynical regarding the motives of others. In a dark inversion of the strong family bonds typical of their dwarven kin, duergar viewed their kin and clan as adversaries set on holding them back, an expectation that became a self-fulfilling prophecy since every duergar came to believe this from early childhood. As a result, duergar were a dark and cruel race, who showed no mercy to their foes and who took great pleasure in inflicting pain on others, a welcome relief from what they believed was a meaningless life, that would end, inevitably, in betrayal.

Culture
Duergar were, as a whole, generally cruel and malevolent creatures, but as in most evil races this was as much a cultural affectation as a psychological trait. A few duergar turned away from the worship of the wicked gods who ruled over the duergar such as Laduguer and Deep Duerra and found salvation through the Morndinsamman. Other duergar found escape from their society through petty crime, tattooed and cast out from their cities beneath the surface and driven into the arms of other races. Their grim disposition, however, made them unlikely to form many lasting friendships.