The Askellon Sector is host to many Forge Worlds of the Adeptus Mechanicus, the greatest of which is Cerix Magnus. It exists in the Mechanicum's own empire that coexists with Imperial authority in the sector. Despite this, Cerix, and to a lesser extent its two sister Askellian Forge Worlds Selvanus Binary and Core Theta, are as reliant on the sector as it is on them, for without raw materials from elsewhere, the forges would sputter and grow cold.
Cerix Magnus must have been settled soon after Askellon's founding, for it has been populated by the servants of the Machine God or their predecessors for as long as any record states. The world's ancient history is largely unknown outside of its own data-repositories, and the masters of Cerix Magnus refuse outsiders access to their archives. It is assumed that the world was host to some engineer caste even before the scions of Mars rose as a power during the earliest days of the Imperium. With the arrival of the Imperial Expeditionary Fleets and the Mechanicum, though, it and its sister worlds were readily transferred to the control of the Machine Cult. Fragmentary records hint at an unnamed treachery during this period, but areas of the three Forge Worlds' archives have been deliberately sealed or even destroyed, and the truth may never be known. Echoes of this terrible occurrence, whispered as the Brass Scouring, still ring across the millennia, however.
Throughout the Age of the Imperium, Cerix Magnus has led the Forge Worlds of Askellon, entering into a number of reciprocal arrangements with other factions including several nearby Knight Worlds. In return for the supply of weapons and other advanced materiel they manufacture, the numerous other worlds serve what needs it cannot meet itself. These range from raw natural resources vital to manufacturing, to Knights and other forces in times of armed conflict, to a supply of sinners to be converted into the many Servitors each forge relies upon for its many tasks.
Outsiders are not welcome upon Cerix Magnus, nor indeed any Adeptus Mechanicus holding in the sector, but those who do have cause to visit the world report that it is hostile to most forms of non-augmented life. The atmosphere is thin, providing scant protection from the baleful radiation cast upon it by the system's bloated star, Cerix Tyrannus. So massive and bright is this star that Cerix Magnus is thought to have had its orbit altered at some point in the distant past in order to survive the periodic solar storms emanating from its photosphere. The planet's surface is cast in ghostly blue light by its star, which despite its great distance looms threateningly in the polluted sky. No oceans exist, and the world's mountain ranges have long since been hollowed out to form the core of its factory-hives. The highest point on the surface is Assembly Zero-One-Zero, a mountain hive city rearing almost twenty kilometres into the atmosphere, its interior plunging so deep into the crust it is thought to penetrate the mantle below. Assembly Zero-One-Zero is the seat of the ruling council of Cerix Magnus -- the Quorum Primus -- a body that has absolute power over every servant of the Omnissiah on the planet, and that has nominal command over Selvanus Binary, Core Theta, and the many lesser Forge Worlds across the sector.
Recent centuries have seen such stopovers grow ever more perilous as the Pandaemonium becomes steadily more severe. Several binaric legends on Cerix Magnus cant that during the mythical Scouring, an entire Forge World vanished from record, along with a blessed Adeptus Titanicus force. Many Tech-priest Questors are certain that somewhere, buried in the devastated wastes of a lost world, lies an entire legion of the most formidable war machines ever to walk the battlefields of Mankind's wars. Should these Titans be discovered, the sector would surely tremble beneath their metallic feet.
Cerix Magnus produces a massive range of weapons and other advanced materiel, but over the millennia has established itself in a number of specialised areas. It is perhaps best known for superior technologies that rely on exotic field effects. These range from plasma containment systems to personal field projectors, but at the more rarefied extremes include teleportation devices and Gellar Field systems based on venerated, ancient templates. In addition to its primary function as a centre of advanced manufacturing, Cerix Magnus sometimes serves as a layover point for Adeptus Mechanicus Explorator Fleets that roam the sector and beyond in search of archeotech and other treasures.
- Dark Heresy: Core Rulebook (Dark Heresy 2nd Edition) (RPG), pg. 341