Sagittarus Malacque was a Custodian of the Legio Custodes, the elite bodyguard of the Emperor of Mankind during the Great Crusade and Horus Heresy eras of the 30th and 31st Millennia. Sagittarus would be the first Custodian wounded unto death and interred within the sarcophagus of a Contemptor Pattern Dreadnought within the Custodes' Moritoi caste.
Sagittarus Malacque was one of the first thirty Custodians created by the hand of the Emperor and served alongside his liege in His personal Honour Guard during the Unification Wars. Sagittarus took part in the epic Battle of Red Frost against the Maulland Sen Confederacy of Nordyc (Scandinavia). Sagittarus and his fellow Custodians stood alongside a few thousand proto-Astartes of the newly created Thunder Legion, with the Emperor leading the Imperial forces Himself. The Emperor utilised Sagittarus' own Guardian Spear to signal the Thunder Legion to advance. Despite being outnumbered seven-to-one and suffering several thousand casualties, they ultimately triumphed over the horde of genetically-altered warriors, witch-marked men and zealots that followed the Priest-King of Maulland Sen. The Priest-King was captured by the Custodians. After the battle Sagittarus witnessed the Emperor carry out his execution and hold aloft his severed head to the baying cheers of the Thunder Warriors.
Choleric and wild, Sagittarus was the first Custodian to be mortally wounded, and entombed within a Contemptor Pattern Dreadnought, whose carapace bore the words "Only in death does duty end" carved in the hand of the Emperor Himself. The Dreadnought called Sagittarus would be armed with a Dreadnought-sied Power Fist with a built-in Plasma Gun and a Kheres Pattern Assault Cannon.
Following Magnus' folly, when the Primarch of the Thousand Sons utilised sorcery to send a message to warn the Emperor of Horus' fall to Chaos, the wards sealing the Imperial extension into the Webway beneath the Imperial Palace from the Warp were broken, which allowed the daemonic legions of Chaos to encroach upon the portal that led into the Imperial Palace itself. Thus began the War Within the Webway. Sagittarus was awoken from his long slumber in order to take part in the fighting against the daemonic hordes of Chaos. Though he was badly damaged while fighting against a Mechanicum construct known as the Archimandrite that was possessed by the daemonic entity Drach'nyen, he would later be saved by the efforts of Arkhan Land.
- Master of Mankind (Novel) by Aaron Dembksi-Bowden