The place where every story ends.
A location referenced in Chapter 102 by the Yellow King, reachable by traveling east (in other words, away from civilization) from the Forsaken Caravanserai across the Eastern Desert.
Implied to exist either in the thin borderlands between the Dreamlands and the Dimension of Dreams proper, or (possibly) in the actual Dreaming, or (possibly) in/at the edge of oblivion… or worse.
Dora and Vik recognized it in Chapter 125 as a body of black liquid, the evaporation of which forms pools of Nepenthe on the moon of the Dreamlands.
In the Act IV Prologue, Ray was seen standing on its shore at an unknown point in time, waiting for something.
First Reference: Chapter 102
Other Notable References: Chapter 125, Act IV Prologue