|Adeptus Astartes Homeworld, Inquisitorial Fortress
In pre-Imperial times, Titan was part of the Saturn polity which was defended by the Saturnine Fleet. Titan, along with the rest of Saturn and its moons, were eventually absorbed into the fledgling Imperium during the early Great Crusade.
Later under order of Malcador the Sigillite, ships and supplies were quietly siphoned off other projects and covertly sent to Titan under the code name Othrys. These shipments were discovered by Administratum Scribe-Adepta Second Classificate Katanoah Tallery when she was processing cargo shipping through the Riga Orbital Plate over Terra, and she believed that they represented a Horus-backed plot to undermine the Imperium via the Departmento Munitorum. An attempt to alert others to the discovery caused her to be hunted, but she was rescued by Nathaniel Garro who believed her story about a possible threat to the Imperium. He was aboard the plate searching for Saint Keeler, and Tallery's devotion to the Lectitio Divinitatus persuaded him to her honesty.
After slipping aboard a derelict ship sent to be used as material to build a fortress monastery on Titan, they managed to navigate through various construction sites as they discovered esoteric weapons being shipped in and the arrival of the Mertiol wounded arriving. They managed to fight their way to the top of the newly constructed fortress only to find Malcador awaiting them. Upon discovery, Malcador revealed that it was not a traitorous plot but one that would ensure humanity would be able to fight the growing threat of Chaos after the Horus Heresy came to an end. However, Tallery could not live with the knowledge, and Malcador ordered Garro to execute her. Garro rebelled against the order, and Malcador relented, taking Tallery into confidence and putting her to use in completing the facility as Curator-Adepta Primus.
Shortly before the Siege of Terra Titan and the remaining Knights-Errant, through Malcador's mystical means, was hidden away from the traitorous Warmaster Horus. When Titan eventually returned after the Heresy, the Citadel of Titan had been constructed along with the creation of the 666th Space Marine Chapter, the Grey Knights. Whilst in the Warp, time had passed at a greater rate for Titan and so it had emerged not with the original eight Space Marines and their raw recruits, but with a full Chapter of one thousand fully trained Battle-Brothers.
Under the surface of Titan lies a cool, damp crypt. It is here that every Grey Knight wishes to finally reside, in the hallowed halls of the glorious dead. Almost every member of the chapter will have their body recovered and brought to this crypt beneath the Emperor's Temple. As a final tribute to those that have given their lives, the names of the dead are carved ceremoniously into a great basalt wall in the heart of the fortress. Among these names are some of the Imperium's greatest heroes who died in the most heroic circumstances imaginable. And like all other matters in regard to Grey Knights, they will remain almost completely unknown.[Needs Citation]
- Archivum Titanis — Volumes of battlefield reports conducted by Grey Knights are stored within the shelves of the Archivum.[1a]
- Cloister of Sorrows — This is a chamber that is open to the night sky of Titan. It's atmosphere is contained in an electromagnetic shield which allows a Grey Knight to be alone with their thoughts as they gaze into the stars.
- Fallen Dagger Hall — A gathering hall named after Grand Master Kolgano who challenged the Grey Knights under his command to an unarmoured dagger duel with the winner getting his jewel-encrusted Terminator armour. It serves as a place for close combat training for new recruits, drills and sometimes for meetings with the Ordo Malleus.[1b]
- Mandulian Chapel — This is a long gallery named after Grand Master Mandulis who died a thousand years ago. It is filled with a high ceiling along with thick columns of statues of Imperial heroes said to represent the different organisations that kept the Imperium together. At the end is a huge three panelled altar and at the front of the chapel is an ornate statue of Mandulis.[1c]
- The Citadel of Titan — This is the Fortress Monastery of the Grey Knights. It nests on the Shadow of Mount Anarch which juts from the ice sheets and oceans of liquid methane like a jagged black spire. The caverns beneath Mount Anarch are said to be haunted, and Paladin aspirants must spend time in them without losing their sanity.[3a]
- Dead Fields — These catacombs serve as the final resting place of fallen Grey Knights. Each chamber contains the dead of an entire century. Individual tombs are marked by a plaque and a statue of the interred Grey Knight[5a]. Within the Dead Fields, lies the Tomb of the Eight. The Tomb of Eight is the resting place of the first eight Grand Masters.[5b]
- Apex Cronus Bastion — A gigantic space station orbiting the planet, it is the size of a small moon. It is one of the most formidable starforts in the Imperium, surpassing even The Phalanx in firepower.[5c]
- Broadsword Station — An orbital station that serves as headquarters for the Grey Knights fleet
- Deimos — Forge World that supplies the Grey Knights and Ordo Malleus. Hangs in orbit over Titan.
- 1: Grey Knights (Novel)[Needs Citation], pg. 67
- 2: Hammer of Daemons (Novel), [Needs Citation], pg. 16
- 3: Codex: Grey Knights (5th Edition), pg. 8
- 3a: pg. 30
- 4: Battle for the Abyss (Novel), Chapters 1–7 passim
- 5: The Emperor's Gift (Novel)
- 6: Codex: Grey Knights (7th Edition) — Deeds of Legend
- 7: Garro: Shield of Lies (Audio Book)
- Codex: Daemonhunters
- Index Astartes — Purge the Unclean; White Dwarf Issue 260 (Australian Edition)
- John Blanche, www.tearsofenvy.com
- Warhammer 40,000: Dark Millennium (1994, for second edition), pg. 22
- The Inquisition (Background Book)