Mars

Mars is the ochre second heart of the Imperium and the first, greatest, and most sacred of its forge worlds. The Red Planet's ancient deserts vanished long ago beneath a global crust of manufactorums, refineries, and hive-forges whose furnaces have not cooled since the Age of Strife. It is the throneworld of the Adeptus Mechanicus, the machine-priesthood whose reach extends into every corner of the Imperium's industry.

The tech-priests of Mars do not worship the Emperor as god, but rather the Omnissiah, the Machine God whose truths they believe are written into the workings of every mechanism. They hoard the relics of humanity's lost golden age and pursue the recovery of the sacred Standard Template Construct designs with the fervour of zealots, for to them the rediscovery of old knowledge is a holy sacrament and innovation a kind of blasphemy.

Beneath the smog-choked Martian sky lie labyrinthine vaults, forge-temples, and the vast Noctis Labyrinth, where secrets of the Dark Age of Technology are guarded and imperfectly understood. From these depths march legions of skitarii, cohorts of battle-servitors, and the towering war-engines of the Titan Legions, an arsenal that makes the Priesthood a power in its own right.

Bound to Terra by the ancient Treaty of Mars, the Red Planet remains a strange and separate realm, keeping its own culture, its own armies, and its own councils of magi. Yet its independence is more than ceremony, for the Imperium cannot fight without the weapons Mars forges. The chronicle of that pact and its priesthood is preserved in the annals of the Mechanicum of Mars. Whoever holds Mars holds the hammer of humanity, and its Fabricator-General wields influence to rival the High Lords of Terra themselves.