Ultramarines

The Ultramarines are a First Founding Space Marine Chapter, raised as the XIII Legion under the primarch Roboute Guilliman. Loyal to the Emperor of Mankind throughout the Horus Heresy, the Chapter is reckoned among the most honoured of the Adeptus Astartes and serves as the foremost exemplar of the Codex Astartes, the treatise on Space Marine organisation that Guilliman himself composed. It remains active in the present age following the Indomitus Crusade, and for much of its history has been led by Chapter Master Marneus Calgar.

The Ultramarines are based on Macragge, chief world of the Five Hundred Worlds of Ultramar in the Segmentum Ultima, where their fortress-monastery, the Fortress of Hera, stands; from there the Chapter administers Ultramar as an Imperial domain, combining military command with civil governance in a manner reflecting Guilliman’s own teachings. The Chapter is recognised by its lapis-blue power armour trimmed in white and gold. Ultramarines gene-seed is recorded as unusually stable, and roughly two-thirds of Space Marine Chapters across the Imperium trace descent from the original Legion, whether as direct successors or through later tithes of Ultramarines gene-seed.

As the War-Born XIII Legion, the Ultramarines fought throughout the Great Crusade under Guilliman, who typically consolidated conquered worlds into stable, self-sufficient Imperial holdings before moving on. During the Horus Heresy the Legion was drawn into the Battle of Calth, where the treachery of the Word Bearers and the resulting warp disturbance known as the Ruinstorm isolated much of the eastern Imperium for years; in the same period Guilliman, together with his brothers Sanguinius and Lion El’Jonson, oversaw the short-lived Imperium Secundus centred on Macragge. Guilliman later fell to the Daemon primarch Fulgrim at the Battle of Thessala in 121.M31 and was placed in stasis for ten thousand years before his revival near the close of the forty-first millennium, an event followed by the Indomitus Crusade that he led to relieve besieged Imperial worlds. In the intervening millennia the Chapter also suffered heavy losses defending its homeworld during the Battle of Macragge against Hive Fleet Behemoth, under the command of Marneus Calgar.

Because of their size, discipline, and the wide dispersal of their gene-seed, the Ultramarines and their many successor Chapters have stood at the forefront of the Imperium’s wars against traitors, aliens, and daemonic incursion since the Chapter’s founding, and their counsel carries particular weight when Space Marine commanders gather to plan campaigns. Notable Ultramarines include Uriel Ventris, a captain whose campaigns are recorded among the Chapter’s more recent chronicles. The Chapter’s history remains closely bound to that of Guilliman, whose return in the present era has renewed the Ultramarines’ standing as the Imperium’s foremost exemplar of the Codex Astartes.