Description
Duergar are dwarves whose ancestors were transformed by centuries living in
the deepest places of the Underdark. That environment down there is saturated
with strange magical energy, and over generations, early duergar absorbed
traces of it. They were further altered when mind flayers and other
Aberrations invaded and performed horrific experiments on them. Fueled by
Underdark magic, those experiments left early duergar with psionic powers,
which have been passed down to their descendants. In time, they liberated
themselves from their aberrant tyrants and forged a new life for themselves in
the Underdark and beyond.
Origins
Duergar were created by Maldos and Zeriax, like all dwarves. Their religion population statistics are Zeriax 60%, Maldos 30%, Other 10%
Genetics
Duergar show some psionic capabilities and superior drakvision. Due to their prolong isolations from the surface societies, they tend to lack some morals of the surface dwellers often being more inclined towards evil than their surface dwarves.
Lifespan
Around 350 years
Homeland
Unknown
Also found in
Reputation
They have reputation of excellent hunters and guides through dangerous underground passages but amongst other dwarves they are considered suspicious and often viewed as thieves.
Alive/Extinct
Duergar have appeared during the 2nd era for the first time and exist until the 4th era.

Duergar Traits
As a duergar, you have the following racial traits.
Ability Scores: increase your Intelligence by 1.
Creature Type: You are a Humanoid. You are also considered a dwarf for any prerequisite or effect that requires you to be a dwarf.
Size: You are Medium.
Speed: Your walking speed is 30 feet.
Darkvision: You can see in dim light within 120 feet of you as if it were bright light and in darkness as if it were dim light. You discern colors in that darkness only as shades of gray.
Dwarven Resilience: You have Resistance to Poison damage. You also have Advantage on saving throws you make to avoid or end the Poisoned condition..
Dwarven Toughness: Your Hit Point maximum increases by 1, and it increases by 1 again whenever you gain a level.
Stonecunning: As a Bonus Action, you gain Tremorsense with a range of 60 feet for 10 minutes. You must be on a stone surface or touching a stone surface to use this Tremorsense. The stone can be natural or worked.
You can use this Bonus Action a number of times equal to your Proficiency Bonus, and you regain all expended uses when you finish a Long Rest.
Languages: Your character can speak, read and write (writing requires INT score 6 or higher) Common and Dwarvish or one other language of your choice that you and your DM agree is appropriate for your character's backstory. A list of languages and their regions can be found in Languages.