Sangprimus Portum

The Sangprimus Portum is an ancient Imperial artefact that contains the potent genetic material harvested from the Primarchs themselves. This artefact was entrusted to Archmagos Dominus Belisarius Cawl by the Ultramarines Primarch Roboute Guilliman shortly after the Second Founding in the early 31st Millennium. Nearly every Space Marine created since the First Founding possesses nineteen specialised organs derived from this gene-seed. The Primaris Space Marines, however -- originally engineered by the Archmagos Dominus Cawl on the orders of Roboute Guilliman -- are implanted with a further three additional organs. It was this device that allowed for this breakthrough and resulted in a new breed of Adeptus Astartes. Due to Cawl's interpretation of his orders and the millennia-spanning labour of his task -- during which Guilliman was injured and suspended in stasis -- the secrets of these new Primaris organs were not released until late in the 41st Millennium.

The Primaris Space Marines were presented to Guilliman after his resurrection in 999.M41, and were deployed en masse in the Ultima Founding, bastions of hope in a galaxy torn apart by the Great Rift, that formed in the wake of the destruction of Cadia during the 13th Black Crusade. This massive warp rift tore through the materium and spread across the galaxy from the Eye of Terror to the Hadex Anomaly in the Eastern Fringe. The Indomitus Crusade saw them spread throughout the galaxy as part of Guilliman's strike against a new age of darkness, to lend their strength wherever it might be needed.