Forge World

A Forge World is the Imperial term for the numerous planets that are directly controlled by the Adeptus Mechanicus. All have in common a complete dedication to the manufacture of the various machines and devices of the Imperium, the pursuit of and preservation of (ancient) scientific and technical knowledge and the worship of the Machine God. Because of the Adeptus Mechanicus' monopoly on technical knowledge and expertise in Imperial culture, the Forge Worlds are the Imperium's primary source of all kinds of hardware: from farming equipment to war machines such as starships, tanks, aerospace fighters, or even Titans. Ancient pacts between the Adeptus Mechanicus and other worlds and institutions of the Imperium oblige the various Forge Worlds to supply other planets and the various military arms of the Imperium such as the Imperial Guard with the products of their manufactoria.

Much of a Forge World is like an immense factory, with industrial complexes soaring into the sky and mine workings burrowing deep into the planetary crust. Forge Worlds build great numbers of complex technologies, like tanks or spacecraft parts for the Imperial Guard and the Imperial Navy. They are ruled by the Adeptus Mechanicus, whose training and research facilities are located there, along with the grand cathedrals to their deity, the Omnissiah, in which the ruling Archmagi of the Tech-priests enact the grandest, most complex rituals to honor the Machine God. The Adeptus Mechanicus’ fleets, its armies of cybernetically-enhanced Tech-Guard warriors and, most formidably of all, the Titan Legions, are also all based on Forge Worlds. The Forge Worlds are largely autonomous from the rest of the Imperium, as allowed by the terms of the Treaty of Mars that founded the Imperium in the 30th Millennium, and the Adeptus Mechanicus is loath to allow anyone on their surface other than Tech-priests and the legions of menial, cybernetic Servitors who labour for them.

The surface of a Forge World is normally completely covered in massive factory complexes that stretch across the horizon. Its ecosystem has been completely destroyed. The air is saturated with toxic gases and rivers flow with toxic runoff from the multitude of manufactoria. In many cases, even seas and oceans have been purposefully evaporated to make room for more manufactoria. However, the sheer amount of industrial output greatly benefits the Imperium as a whole. All of the items produced by a Forge World are constructed according to a very specific design formula that varies from Forge World to Forge World, even for otherwise identical pieces of the same equipment and these variant designs are known as that Forge World's "pattern."

The Forge Worlds were settled by Cult Mechanicus colonists sent from Mars, the first of the Forge Worlds, during the Age of Strife. Despite the difficulties with Warp travel during that period as massive Warp Storms consumed the galaxy during the gestation of the Chaos God Slaanesh in the Immaterium, several interstellar expeditions were able to make their way across the galaxy, either using the Warp during a period when there were few storms or travelling at sub-light speeds in realspace. Hundreds of Mechanicus colonies were settled across the galaxy spreading their faith into every corner of human-settled space. These planets were allowed to remain under the direct sovereignty of the Mechanicus under the terms of the Treaty of Mars that the Emperor of Mankind signed with the Mechanicus to unite Terra and Mars beneath the aegis of the Imperium of Man in the late 30th Millennium.

While there are hundreds of Forge Worlds in the Imperium, the most important is Mars, home of the Adeptus Mechanicus' political and spiritual head, the Fabricator-General of Mars; and the Imperium's first Forge World. Other Forge Worlds include Ryza, known for its advanced plasma technology; Gryphonne IV, home of the Titan Legio Gryphonnicus; Agripinaa, a primary supplier of military goods to the Fortress World of Cadia; Phaeton, manufacturer of the Leman Russ main battle tank; and Urdesh, the primary Forge World within the Sabbat Worlds Sector. Of all the Forge Worlds only Trebor caters exclusively to the industrial needs of Cadia. One of the most sought-after creations from Trebor is its version of the Vanquisher Cannon, which is the most powerful of all the Vanquisher Cannon variants. During the Dark Age of Technology, the twin empires of Terra and Mars co-existed, to the mutual benefit of both. Trebor was colonized from survivors of colony expeditions from both Terra and Mars after they were lost during a Warp storm. This forced both colonies to combine their knowledge and build the most technologically-advanced of all the Forge Worlds. Trebor was only re-discovered by Commissar Yarrick during the Second War for Armageddon in the late 41st Millennium. As a result Trebor has sworn its allegiance only to Commissar Yarrick and to Cadia, and its arms and technology made a major difference in the successful defence of Cadia during the 13th Black Crusade.