Underdark

The Underdark is a vast underground environment in the world of Exandria. A dark and hostile place, the Underdark is almost a world unto itself, with civilizations, monsters, politics, economies, and threats that may interact only sporadically or indirectly with the surface world. Notably, the Underdark has significant connections to the Far Realm, from which many aberrations emerge.

Society

Tal'Dorei

• Crystalfen Caverns: Deep beneath the Bladeshimmer Shoreline and even running beneath the ocean floor, the caverns were colonized before the Age of Arcanum by aboleths and other aberrations from the Far Realm. That civilization was gradually expanding toward the surface until it was literally crushed by forces unleashed in the final battle of the Calamity that tore through Exandria. Because of long exposure to psychic energies, the caverns have veins of azuremite, one of the substances that can be refined to make suude.
  Ruins of Salar: Salar, the Unseeable City, was the capital of the aberrations' civilization. Trysta excavates and studies the ruins.
• The Emberhold: A duergar stronghold accessible via the mines beneath Kraghammer, after miles of walking. Came under K'Varn's control.
• Yug'Voril: An ancient city lately controlled by an illithid colony that also fell under K'Varn's thrall. Even the illithid don't know who originally built it. Close to a rift with the Far Realm. Nearby there are veins of blue crystal matching the description of azuremite.
• Vulkanon: The city-state, deep in the magma tunnels of the Cliffkeep Mountains, that serves as the center of fire giant civilization. Produces high-quality arms and occasionally allies with the duergar of the Emberhold.
• Ruhn-Shak: A small drow city beneath the Stormcrest Mountains, devoted to Lolth, the Spider Queen.

Wildemount

The Kryn Dynasty—particularly the Aurora Watch, with its magically controlled purple worms—largely controls the Underdark of continental Wildemount. They send assassins and spies, collectively called the Lens, through the Underdark to infiltrate other lands and seek out Luxon Beacons.[10] Duergar hostile to the Kryn control perhaps a dozen small outposts. Deep gnomes also have some small settlements in the Underdark, and remain neutral between the Kryn and duergar.

Other Notable Locations

• The Bastille of Torment, deep under the Dunrock Mountains, is presumably part of the Underdark. Torog used the Bastille to torture the enemies of the Betrayer Gods during the Age of Arcanum.
• Fire giant citadel beneath the northern Ashkeeper Peaks
• Miskath Pit In Blightshore, a sinkhole of untold depth that blends the Underdark with the Far Realm.
• The Winding Core: A sliver of the Underdark on Rumblecusp.

Geography

As a subterranean environment, the terrain of the Underdark is composed primarily of earth, stone, water (both still and running), and magma. Passages navigable by humanoids range from narrow tunnels to expansive caverns. Natural cavern formations like stalagmites and stalactites abound; some predators camouflage themselves among them to ambush unsuspecting creatures. Without sunlight, the Underdark exists in a perpetual night with the exception of the light from such sources as fire, bioluminescence, enchanted red glow stones, and magma. Without photosynthesizing plants, fungal growths and even mushroom forests are foundational for the food chain.

Fauna & Flora

Most Underdark creatures either are blind (with no eyes or with vestigial eyes) or have excellent darkvision. Many creatures have other highly developed senses to compensate for the lack of sight, such as tremorsense or a keen sense of smell and/or hearing.Peruse the list below for examples.

Humanoids

• Drow (dark elves)
• Duergar (gray dwarves)
• Goblins
• Kobolds
• Svirfneblin (deep gnomes)

Aberrations

• Aboleths
• Cloakers
• Illithid
• Intellect devourers
• Monstrosities
• Abyssal Abomination - Created by K'Varn
• Basilisks - Kept by the duergar
• Bulettes
• Driders
• Gricks
• Hook horrors
• Purple worms - Kept by the drow
• Ropers
• Umber hulks
• Giants
• Fire giants
• Fomorians
• Ogres
• Trolls
• Fiends
• Draegloths
• Beasts
• Bats
• Small, sightless rats
• Plants
• Gas spores
• Oozes
• Black pudding
• Undead
• Ghouls

Type

Dimensional plane