The Red Seraphs and Angels Numinous are both descended from the Blood Eagles.
The Red Seraphs are the successors of the Blood Eagles, a Blood Angels successor in turn that tore itself in half during an unknown conflict. The two halves of the Blood Eagles then formed their own Chapters, the Angels Numinous and the Red Seraphs.
Those two Chapters joined with another Blood Angels successor, the Charnel Guard, to form an alliance of Sanguinius' sons known as the "Triarchy." Though allied, the Angels Numinous and Red Seraphs Chapters were noted to agree on nothing.
They used the ritualistic phrase, "We are Three, drawn from Two, born of One," to define their traditional partnership and kinship to one another.
It was a tradition of representatives of those three Chapters to meet at the abandoned homeworld of the Blood Eagles to determine a course of action that would involve the entire Triarchy. The ritual words were always spoken by the Triarchy representatives before any conclave could begin.
At one such conclave held after the birth of the Great Rift during the Era Indomitus, Ynoch of the Red Seraphs, Jagudir of the Angels Numinous and Mordath of the Charnel Guard gathered to discuss how the Triarchy would deal with their growing isolation in the Imperium Nihilus, as the Chapters were unable to cross the Great Rift and were coming under increasing threat from xenos and the forces of Chaos.
They decided to reject their traditions, and rather than defend their shrinking domains they would seek out the foes of the Emperor in the Dark Imperium and fight aggressively even if it meant the death of their Chapters. And they promised that if they could find Roboute Guilliman's Indomitus Crusade, they would join it.
- Dark Marches Crusade (610-759.M36) - In the wake of the Age of Apostasy, the Segmentum Tempestus saw a resurgence in power and renaissance of expansion, known to Imperial historians as the "Rising Storm." With the blessing of Terra, Segmentum Tempestus authorities launched a number of crusades and campaigns to destroy lingering threats within their domain, and push back and fortify the borders of the Imperium. The most successful of these was the Dark Marches Crusade, commanded by Lord Tempestus Hal Orpheus, lineal descendant of the Rogue Trader house that had first explored the Orpheus Region's sinister reaches millennia previously. The Red Seraphs sent three companies of Astartes to take part in the massive Imperial Crusade.
- Battle of the Gorgon Deeps (160.M39) - When the Orpheus Sector was attacked by a great Ork invasion, the Red Seraphs and their brothers from the Space Marine Chapter of the Revilers reinforced Battlefleet Orpheus and confronted the Ork menace. In a nineteen-week running space battle, the Chapter eventually succeeded in destroying the Ork flagship Mega-Kroozer by boarding it and planting seismic charges. With the loss of their flagship the Orks scattered but would go on to be a thorn in the Sector's side for centuries to come.
- Magdellan Prime Civil War (143-151.M41) - When the followers of the Cult of Balthalamus plunged the world of Magdellan Prime into anarchy and bloodshed, the battle-sisters of the Order of the Ebon Chalice bore the brunt of the fighting. The Order's Preceptory Reclusium was repeatedly targeted by the maddened hordes, but held out against seemingly impossible odds until relief eventually arrived. By the time a relief force consisting of Space Marines of the Red Seraphs, Fire Angels and Sons of the Kraken Chapters arrived, the battle-sisters had begun a determined counter-attack and victory was ultimately won.
- Orphean War (992.M41) - Eager to aid in the defence of a domain that they had helped to claim in the name of the Divine Emperor, the Red Seraphs sent out troops to the Orpheus Sector to participate in the Orphean War. Although they arrived too late to participate in the disastrous Battle of Amarah, the inbound Red Seraphs are expected to be drawn into the Orphean Salvation Campaign, striking out at the Maynarkh Dynasty of the dreaded Necrons whilst the Imperium fortifies the neighbouring Eurydice Sector.
The Red Seraphs honour their dead with internment inside ornate sarcophagi in the beautiful bowels of their warships.
The Red Seraphs are a very tradition-bound Chapter, like all the members of the Triarchy.
Notable Red Seraphs
- Ynoch - Ynoch was the representative of the Red Seraphs on the Blood Eagles' abandoned homeworld at the Triarchy conclave that made the decision to take the offensive against the enemies of the Emperor in the Imperium Nihilus during the Era Indomitus.
- Misericordiae- A warship of unknown class that bore Ynoch to the Triarchy conclave on the Blood Eagles' abandoned homeworld.
The Red Seraphs' power armour is a rich, blood red. The battle-plate can be marked by oblique runes and decorated with talismans of faith and fury against the foe.
Red Seraph battle-brothers often wear a white linen loros crafted by slaves.
The Red Seraphs' Chapter badge is a robed angel clasping a chalice.
- Imperial Armour Volume Two (Second Edition) - War Machines of the Adeptus Astartes, pg. 20
- Imperial Armour Volume Twelve : The Fall of Orpheus, pp. 17-19, 21, 40
- Aaron Dembski-Bowden's notes
- White Dwarf 454 (June 2020), "Tradition's Last Breath" by Aaron Dembski-Bowden, pp. 42-43