A demi-plane splintered off from the Shadowfell millennia ago, this realm is under the sway of Orcus. It’s physical entryway to the prime material plane is located beneath what is now the drow city of Phaervorul.
History learned from The Keeper: Centuries ago an exarch of Orcus ruled this place, and sent his minions forth to raid in the natural world. Drow settlements were targeted by the undead, and the drow eventually raised an army to fight back. They were victorious and Orcus, disappointed by his champion, left the exarch at the mercy of the drow. The drow sealed the gateway and built Phaervorul over the planner cyst to guard against future attacks. Centuries passed and Orcus sent a calling out to the drow of Phaervorul. One prince known as Zirithian answered the call and turned from Lolth to pledge fealty to Orcus, in return for power and undead followers.