The duergar, also know as Deep Dwarves, Dark Dwarves or Grey Dwarves, are distant cousins of the dwarves twisted by a long association with devils and infernal forces and now almost exclusively worship devils such as Mammon.
Like their kinsmen they share a love of smithing, stonework and artifice but are almost exclusively treacherous, cruel and evil. 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. 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 the rule of mind-flayers thousands of years ago.
Duergar look similar to their dwarven cousins, though their skin is a much darker shade. Their hair and beards are made of thick quills and spines, like that of a porcupine, and their eyes shine brightly. Unlike their distant kin duergar are able to make themselves invisible, a trait that has served them well in their Underdark homes.