Thanatos

If Orcus had her way, all planes would resemble her dead realm of Thanatos, and all creatures would become undead under her control. Under its black sky, Thanatos is a land of bleak mountains, barren moors, ruined cities, and forests of twisted black trees. Tombs, mausoleums, gravestones, and sarcophagi litter the landscape. Undead swarm across the plane, bursting from their tombs and graves to tear apart any creatures foolish enough to journey here. Orcus rules Thanatos from a vast palace known as Everlost, crafted of obsidian and bone. Set within a howling wasteland called Oblivion’s End, the palace is surrounded by tombs and burial sites dug into the sheer slopes of narrow valleys, creating a tiered necropolis. (Source: DMG D&D 5e)
113th Layer of the Abyss.
It was a frigid and frozen layer infested with the undead. Several cities dotted the layer (most of them ruled by minions of Orcus, including a powerful succubus and Quah-Nomag himself). Orcus ruled from her palace of Everlost in the bone-meal desert of Oblivion's End, north of a vast mountain chain called the Final Hills that cut across the layer. Despite Orcus regaining control over Thanatos, Kiaransalee's taint could still be found in the city of Naratyr on the Frozen Sea south of the layer, and in the so-called Forbidden Citadel in the city of Lachrymosa, located in the Final Hills. (https://forgottenrealms.fandom.com/wiki/Orcus)

Alternative Name(s)

113th Layer

Type

Abyss

Location under

The Abyss

Owner/Ruler

Orcus

Ruling/Owning Rank

Demon Lady

Owning Organization

Cult of Orcus