Built above the ruins of Kathmandu[1a] in the Palace's northern regions[3a], the Sanctum Imperialis lies deep within the Inner Palace, past the Eternity Gate which is permanently guarded by two Titans of the Legio Ignatum. The central area of the Sanctum is an expanse known as the Hall of Widows. Further into the Imperial Palace lies the Imperial Dungeon. The Dungeon was built deep underground by the Emperor to be the linchpin of his grand ambition. After a long journey below the surface of Terra, one finally comes before the last door into the Throneroom of the Emperor himself, which is guarded by a pair of Custodes Contemptor-Galatus Dreadnoughts.[1a] Over the door is the inscription Conservus, Restituere, Revivicarem.
Past the last door the Master of Mankind is eternally seated upon Golden Throne and is accompanied by the 300-strong Hetaeron Guard. Behind the Golden Throne is a dormant Webway Gate, long ago part of the Emperor's ultimate ambition but dormant since being sealed 10,000 years ago. In truth, the Throneroom is itself a massive edifice rather than a simple chamber, for within lies the vast machinery that keep the Golden Throne functional. In the years since the Heresy, the machinery has grown more vast and complex as the requirements to maintain the Throne have increased. The mechanisms of the Golden Throne are like roots that spread all the way to the Astronomicon.
The Tech-priests of the Adeptus Mechanicus constantly maintain the Golden Throne, and they are the only ones besides the Adeptus Custodes and Sisters of Silence allowed to walk these halls. Along the walls of the Throneroom are thousands of outlets connected to the Golden Throne which are inserted with coffins holding a psyker. These serve to initiate the thousand daily sacrifices to keep the Golden Throne operational. Few can withstand to be before the Emperor's presence for very long without being overwhelmed. Even Custodes are are known to fall to their knees before the sight of Him.
The Imperial Dungeon was originally the laboratory where Amar Astarte created the Space Marines. However she destroyed her own lab during the Palace Coup in an attempt to erase her work. The Emperor had foreseen this and copied much of her work, apparently using the lab's destruction as an excuse to clear the chamber for the Webway Project.
- 1: Master of Mankind (Novel) - Part II Choir
- 1a: Chapter 14
- 2: Watchers of the Throne: The Emperor's Legion (Novel) - Chapter 5
- 3: The Lost and the Damned (Novel) -
- 4: Warhammer 40,000 5th Edition Rulebook, p. I
- 5: The First Wall (Novel) Chapter 17
- 6: Valdor: Birth of the Imperium (Novel) Chapters 16-18