Duergar

Duergar, also known as Deep Dwarves or Underdwarves, are a short and stocky subrace of dwarves that dwell in the Underdark's deepest places. Like many other Underdark races, they have developed a natural attunment to magic and most Duergar possess some form of innate magic. They sport the greyish-purpleish skin and white hair that is so common among Underdark species and stand about 4 to 5 feet tall, with a lifespan of about 350 years.
Duergar and regular dwarves do not get along by any means and have fought many wars against each other of the centuries, with the Duergar believing they are true dwarves and uphold the superior form of dwarven ideals. They are quite stoic, mean, greedy, and pessimistic, but also extremely industrious, with their fortresses and cities being some of the most impregnable in all the Underdark and Duergar forged weapons and armor are among some of the most coveted both in the Underdark and on the surface.