Duergar

Duergar, also known as gray dwarves, dark dwarves, and deep dwarves, are a race of dwarves that lives in the Underdark or in places shaded from the scorching sun rays.

Appearance
Duergar are characterized by ash-gray-colored skin and white, pupil-less eyes.

Abilities
In rigid underground world, duergar became hardier, physically enhanced, and adapted toward the surrounding darkness:
 * Increase Size
 * Darkvision
 * Magic Resistance
 * Vulnerable to sunlight

Religion
Two different sources (C1/TCSR) establish two separate entities worshipped in the Emberhold:
 * Laduguer, god of power, strength, and conquest who supposedly freed the duergar from the illithid's control. He was worshiped or mentioned by this name until the stronghold was destroyed in 15 Quen'pillar 810 PD.
 * Azgrah, an extremely old duergar champion who is adored by the dark dwarves of the Emberhold and the surrounding Underdark. He was worshiped or mentioned by this name in the interval between 812 PD and 836 PD, not long after the massive changes in the Emberhold society.

Due to their similarities, it's possible they are two aspects of the same deity, or that one took the attributes of the other, although they have different alignments and type of worshippers (the first one having his own clergy, while the second one is served by warlocks).

Additionally, the nobles and monarchs worship the Crawling King, who send monsters whenever he detects impiety among them.

Tal'Dorei
The duergar of the Emberhold seem to have very similar technological styles to the other dwarves. They had a king and queen, but after they were killed, the bloodline of a lesser war-duke, Thangrul, took their place in the hierarchy. In 812 PD Tal'Dorei, the duergar are widely considered evil, and the dwarves of Kraghammer have little idea of why the duergar kept launching raids against the city. The duergar, in turn, whisper fearfully of the mind flayer colony of Yug'Voril. As of 836 PD, many duergar perched a secret hope to ally with their other dwarf kin, only waiting for someone brave enough to reach out with good faith.

The duergar of the Emberhold have domesticated basilisks as weapons to be used in combat.

Wildemount
A small portion of duergar peoples agreed to join the Kryn Dynasty and live within the auspiciously shaded lands of Xhorhas, making up the 7 percent of Rosohna's population, while the more conservative kind are fighting against the dynasty for their own territory beyond the Underdark.

Pre-Stream
Some speculate that duergar are descended from a group of dwarves who delved far into the subterranean Tal'Dorei countless centuries ago, predating even the chronicles of Kraghammer. The magic changed the deep dwarves who settled deep in the underground realm, becoming duergar.

Campaign One: Vox Machina
Vox Machina fought many duergar during their time in the Underdark. They also infiltrated a duergar stronghold called the Emberhold and killed the king in battle. The queen then disintegrated a section of the roof, causing the Emberhold to flood with magma as she retreated.

Known Duergar

 * King Murghol: King of the Emberhold and a formidable fighter, he was decapitated by Scanlan in combat.
 * Queen Ulara: Queen of the Emberhold and a sorceress, she was psychically killed by K'Varn.
 * Murghol and Ulara's daughter:
 * King Thangrul II: Following the death of king Murghol, the now former duke was coronated in 812 PD as the king of the newly rebuilt Emberhold, still rulling his domain in 836 PD.
 * Unidentified duergar prince: A nobleman of the grey dwarves in the Cliffkeep Mountains died in or prior to 812 PD.
 * Unnamed General: Head of the duergar army underneath Kraghammer. He was killed by Clarota consuming his brain.
 * Besh Turmin: Shopkeeper in Rosohna.
 * Roguun: A blacksmith working for Huron Stahlmast in his lair above Hupperdook.