|Map||Basic Data||Planetary Image|
|Class:||Forge World, Segmentum Fortress|
Orbiting Hydraphur is the massive Star Fort Ascendant as well as massive shipyards which ring the world. These artificial rings, while not as large as those on Luna or Mars, serve as the fleet base for Segmentum Pacificus. However the world itself is divided into several spheres of influence. The Imperial Navy holds sway in the atmosphere and above, while on the surface the Ecclesiarchy rules in uneasy conjunction with the Adeptus Mechanicus.
During the Plague of Unbelief, Hydraphur surrendered to the rebel forces of Cardinal Bucharis, to the lasting shame of its subsequent generations. After Hydraphur's return to the fold of the Imperium, Cardinal Chye Balronas instituted an annual religious festival characterized by fasting and penitent observance.[2a] Another legacy of the Plague was the Administratum's attempt to curtail the power of the Imperial Navy in the system. Although the Hydraphur system was a centre of Fleet operations, the administrative presence of the Ecclesiarchy and the Inquisition were increased, while the landholding Naval families on Hydraphur were gradually relieved of their possessions. However, the success of the partition was mixed: although the primary authorities on Hydraphur itself are the Administratum and the Ecclesiarchy, the Navy responded by tightening its control over the rest of the system and subsector[2b], to the point where the Ecclesiarchy on Hydraphur found it necessary to use covert couriers to communicate with its fellows in other systems[2c]. The Navy also formed close ties with the mercantile families on Hydraphur, such that their syndicate ties were regarded as family associations.[2b] Due to the strife on Hydraphur during the Age of Apostasy, the world was ultimately divided between the Navy, Ecclesiarchy, and Mechanicum thanks to reforms overseen by Balronas[2a].
Sometime after the Great Rift's creation, Hydraphur was invaded by the Black Legion and the Imperium sent its forces to defend the world. However, the Black Legion advanced in great numbers, which forced the defenders to retreat - save for the Adeptus Custodes. No matter how many times the Black Legion charged the Custodes, they have stood firm and have broken the traitors' advance against their Auramite wall. By the early days of the Indomitus Crusade it had been assailed 3 times by the forces of Chaos.
- 1: White Dwarf issues 139 and 140, Interstellar Travel, by Jervis Johnson, Andy Jones, Simon Forrest and Rick Priestley
- 2: Crossfire (Novel) — Enforcer: The Shira Calpurnia Omnibus by Matthew Farrer
- 3: Codex: Adeptus Custodes (8th Edition), pg. 7 — Brotherhood of Demigods
- 4: Avenging Son (Novel)