Demiplane of Nightmares

The Demiplane of Nightmares was a demiplane coterminous with both the Ethereal Plane and the Region of Dreams. The boundary between the Demiplane of Nightmares and the Far Realm was very thin, and Far Realm taint continually leaked into the demiplane, corrupting all it touched.

Description
The Demiplane of Nightmares was described as a place whose angles, geometry, and inhabitants seemed disturbing by human standards. On this plane, a traveler's darkest thoughts and fears became reality.

Inhabitants
Inhabitants of the Demiplane of Nightmares included neh-thalggu, diaboli, feyrs, nagpas, maelephants, and others.

The diaboli occupied the same niche on the Demiplane of Nightmares that humans did on the Material Plane

While neh-thalggu were not native to the Demiplane of Nightmares, they occupied a place in diabolus myth and legend roughly equivalent to the place dragons held in human stories.

History
In, Netherese arcanists emigrated to the Demiplane of Nightmares, where the energies infusing the plane twisted their descendants until they evolved into the Night Parade.

Around and prior to the year, members of the Night Parade opened portals back to the Realms, where they began infiltrating cities such as Calimport.

Rumors & Legends
Some claimed that the dark powers must have pulled part of the Demiplane of Nightmare into the Demiplane of Dread to create an even more terrifying expanse in that place.