Phalanx is no world of rock and soil but a star-fort of impossible scale, a fortress the size of a moon that drifts through the void as the mobile home of the Imperial Fists, a chapter of the Space Marines. Predating even the coming of the Emperor's crusades, it was claimed by Rogan and gifted to the primarch Rogal Dorn, who wrought it into the mightiest siege-engine ever to sail the stars. Its batteries could crack a planet; its docks could swallow whole battle-fleets whole.
Within its endless corridors of adamantium and ceramite lie chapels, forges, apothecarions and the sealed vaults where the chapter's most sacred relics are kept. Countless generations of the sons of Dorn have trained, prayed and died within its halls, and the walls themselves are graven with the names of the honoured dead. To walk Phalanx is to walk through ten thousand years of grim Imperial history.
When the Iron Warriors betrayed their brothers in ages past, they broke themselves against Phalanx's shields, for no traitor has ever taken it by force. It answers only to the Master of the Fists, and where it appears in the night sky of a besieged world, hope or terror follows in its wake. In the endless war of the 41st Millennium, Phalanx remains a bastion that cannot be conquered, only endured against.