The Stagnant Demesne is the second extra episode for Heretic: Shadow of the Serpent Riders expansion.
In this episode, the player enters D'Sparil's home stronghold - the very pit from which he was spawned. Corvus seeks to find a way out, yet D'Sparil's personal guards are out to kill him. The fifth episode was designed to be the hardest episode of the game. Like "The Ossuary," and "Thy Flesh Consumed" from Ultimate Doom, there is no intermission screen as the player progresses between maps.
Level themes are mostly similar to those of episode 3.
The music was previously used in episode 2, including "The Skein of D'Sparil" reusing the music from "The Glacier" (despite that that episode's secret level came after its fourth level, whereas this episode's secret level came before its fourth... although because "The Catacombs" had previously reused music from "The Guard Tower," therefore so did "Hydratyr."
Sky Color: Blue (same as episode 3)