Duergar are a dwarven people who have historically been considered cursed and viewed as outcasts by other dwarves.
History
The origin of the duergar is told in the shared legends of the dwarves. In the semi-mythical Kingdom of Gold and Iron, the earliest nation of the dwarves, the various clans were given certain roles to fulfill in the maintenance of an orderly society. Those that became the duergar were the guards of the Kingdom, tasked with defending it against the many dangerous threats of the Depths. Though capable builders and soldiers, with time the clans grew excessively proud and self-confident in the fortifications they had built. They disregarded their duties for too long, and eventually in one impossibly large assault the monsters of the dark overwhelmed the walls of the Kingdom. As their promenades, palaces, and workshops alike were overrun, the dwarves fought as long as they could but were eventually forced to flee, scattering through the Depths. Most made their way to the surface for the first time, while others remained underground as they attempted to set up new realms in the image of the Kingdom. For their part in allowing the Kingdom to fall, the clans that neglected their responsibilities were cursed, turning into the duergar.
The duergar have been viewed as outcasts since, shunned from the cities of other dwarves and left to fend for themselves against the threats of the underground. Some view the stories of their origin as literal, a divine retribution for the failings of their ancestors, while others believe their physical differences from other dwarves to have come about as a result of many generations living amongst the strange forces and phenomena of the farthest levels of the Depths.
Culture
Other dwarves have long held many negative beliefs about the duergar, often refusing to allow the duergar access to their cities, engage in trade with them, or even speak with them. In more recent centuries this treatment has softened somewhat, largely as a result of increased contact with the duergar of Barazar El, but many traditionalist dwarves remain prejudiced to their kin.
Duergar are often skilled survivalists, highly adept at navigating the many hazards of subterranean life. They build their settlements in hidden places, obscured from any who might wish harm upon them, only coming and going via well-protected routes that can be easily collapsed if a threat arises.
Location
The majority of duergar live either in the deep sea communities of Barazar El, or else in remote, largely isolationist settlements in the Depths, away from major routes of travel.