The Red Angel is a daemon of Chaos which was formed from the distilled rage of Brother-Captain Tagas, the former Captain of the Blood Angels Legion's 111th Company, who had been presumed killed in action on the world of One-Forty-Twenty, the planet called Murder.
Through the dark sorceries of Chaos, the undiluted rage of the Blood Angels gained sentience, giving birth to the vile creature known as the Red Angel. During the opening years of the Horus Heresy, this daemon came to possess the body of Apothecary Meros of the Blood Angels during the Battle of Signus Prime.
The Red Angel was created during the opening days of the Horus Heresy by possessing the body of Brother Meros, an Apothecary Minorius (a junior medicae) who served in the Blood Angels Legion's 9th Company under the command of Captain Furio during the Great Crusade and Horus Heresy. Initially, Meros was a simple line-Astartes of solid, if unremarkable service. But later on, during the opening days of the Heresy, his fate would become inextricably intertwined with that of his Legion and his Primarch Sanguinius during the Signus Campaign.
It is said that Horus hated and feared Sanguinius more than any of his brothers and wove many strategies to ensnare or slay him, though all failed. In an effort to weaken and divide the Loyalist forces, the Warmaster charged the Blood Angels Legion with the arduous task of cleansing the Signus Cluster -- a triple star system of the Segmentum Ultima near to the galactic centre.
Sanguinius' Legion was ordered to cleanse the 7 worlds and 15 moons of the Signus Cluster of xenos invaders and release the humans thereon from their xenos-overlords. Unaware of the Warmaster's perfidy, Sanguinius willingly obeyed his brother Primarch and immediately set out for this volatile region of space. Unbeknownst to the Blood Angels, they were blindly walking into a deadly trap, for the Signus Cluster had fallen prey to agents of the Ruinous Powers and become a veritable Realm of Chaos -- a system of hellish Daemon Worlds under the rule of a Greater Daemon of Slaanesh known as Kyriss the Perverse.
Rising to the challenge of the vile Greater Daemon, the Blood Angels Legion attacked the daemon host of Kyriss, launching a series of attacks across the seat of the daemon's power, the world of Signus Prime. The Primarch spearheaded the Blood Angels' assault on the Greater Daemon's seat of power, known as the Cathedral of the Mark, to confront and destroy Kyriss and reclaim the planet in the name of the Emperor.
When the Primarch was struck down by Ka'bandha, a Greater Daemon of Khorne, the Blood Angels were consumed by a black rage that drove them into a berserker's fury as they charged into the daemonic horde. In their madness they smashed the horde of daemons asunder. A small cadre of former Librarians used their combined psychic abilities to heal their Primarch and wake him from his dark torpor, bringing him back from the edge of the abyss.
The Angel finally arrived to confront both Kyriss and Ka'bandha. The Bloodthirster and Sanguinius fought once more, but ultimately, the Primarch prevailed and cast the Greater Daemon back into the Warp. The Blood Angels then discovered the source of the rage that had infected their entire Legion.
The Dark Apostle Erebus had created a fell device, a psychic construct known as the Ragefire, which contained and was powered by the half-dead body of Captain Tagas, the former Captain of the Blood Angels' 111th Company, who had been presumed killed in action on the world of One-Forty-Twenty, the planet called Murder by all the Space Marines who had fought there several standard years earlier.
Through the use of the dark sorceries of Chaos, the Word Bearers had created a conduit of undiluted rage that consumed nearly the entirety of the Blood Angels Legion. Driven to uncontrollable rage over their fallen Primarch, the Forces of Chaos hoped that the Blood Angels would lose control of their noble aspect, and willingly give themselves over to the Scarlet Path and the worship of the Blood God Khorne.
Cathedral of the Mark
In bloody defeat, Kyriss the Perverse offered Sanguinius a foul deal: if the Primarch would willingly take the place of the half-dead Tagas within the psychic construct and give himself fully to the Ragefire, he would ensure that his sons would never again be affected by the genetic curse of the Red Thirst. The Primarch seriously contemplated the daemon's offer and finally came to the conclusion that this sacrifice was worth it to save his beloved sons.
But before Sanguinius could enter the construct, Meros made the decision for him, and leapt into the suspended crystal lattice. Sanguinius threw himself into the air in an effort to save his errant son, but was too late. The Apothecary committed the act without uncertainty, for he knew it was right. The Angel could not fall.
When Meros had met the future Blood Angels Sergeant Rafen of the late 41st Millennium in the dreamscape of their joint healing blood-sleep through the timeless power of the Warp, the Blood Angel from the future had said a name, a warning. Only at that moment did Meros fully understand. Sanguinius had to live, in order to meet the Arch-Traitor Horus on equal footing. When the terrible confrontation finally came, the Angel had to be there to face him, brother against brother.
Before Meros stepped into the swirling vortex of undiluted rage, he forcibly and painfully used his cutter to open a jagged tear through the layers of ceramite and flesh beneath. Using the Reductor on his gauntlet's Narthecium, he guided the device as it bore through his skin, and removed his own Progenoid Glands. The device sucked the nodules of gene-rich tissue into a reservoir pod, sealed within for preservation. Meros' bequest to his Legion now lay secured. Detaching the medicae module from his armour he tossed it towards his Primarch, who snatched it out of the air, and requested that Sanguinius take it, so that something of him would live on.
The Angel vowed to honour his son's final request. With this final act, Meros stepped into the whirling vortex. Meros transformed, writhing in the grip of an infernal glow as the burning power merged with every atom of his being. The flesh of his face distorted into a hollow mask far beyond the guise of pain. His armour became dark and disfigured, joints steaming, the shell of it trembling as it fought to contain energies never meant to be bound to this reality.
In the Warp's shadow, a pair of ghostly, blood-drenched wings briefly unfolded from the wounded Apothecary's back, anointing the ruined bones beneath with a rain of phantasmal blood; then they were gone as Meros' body was possessed by a daemon of the Blood God. Brother Meros was gone, and in his place was the daemonic Red Angel.
Confronting the Possessed Blood Angel, Sanguinius demanded that the avatar of hate release its hold on his son. The Red Angel flatly refused. When the Primarch inquired if there was any small part of Meros that remained, the Red Angel responded that there was a small trace of the former Apothecary.
The Primarch told the vile creature to heed his words; whatever Ruinous Powers it served, whatever irrational choice Horus had made to seek a pact with them, they stood defeated this day upon the cusp of victory. Sanguinius vowed that Meros' sacrifice would not be in vain, and that one day, he would find a way to free the Apothecary from the daemon that now possessed his mortal shell. The Red Angel then took its leave from the Cathedral of the Mark and disappeared into a Warp Gate that it conjured.
The Blood Angels completed their purge of the daemons on Signus Prime and even Kyriss the Perverse was sent screaming back to the Warp on the end of Sanguinius' sacred blade.
As for the daemonic entity known as the Red Angel, it presented itself to Horus aboard his flagship, the Battleship Vengeful Spirit. Erebus was infuriated that the Warmaster had interfered with his plans to turn the Blood Angels to the side of Chaos. When Horus asked the daemonic entity its true identity, the Red Angel revealed itself as the Fallen Son of Baal, the Cruor Angelus, the Willing Slave.
The Red Angel was a weapon to be used at Horus and the Traitor Legions' disposal, a weapon intended to seize Terra and throw down the False Emperor. The daemon's statement was met with the Warmaster's approval.
When the daemon named itself the "Red Angel," Horus' Equerry, Maloghurst, warned that the World Eaters' Primarch, Angron, who had already taken this epithet, would be gravely insulted. The Red Angel replied that if the Primarch of the World Eaters took offence, he could challenge the daemon, claiming he deserved it far more than Angron.
Later on, during the Battle of Molech, the Red Angel was utilised by Horus as a guide after he entered the planet's hidden Warp Gate in his bid to obtain the powers he believed granted to the Emperor by the Chaos Gods when he had similarly used the gate.
- Fear to Tread (Novel) by James Swallow
- Vengeful Spirit (Novel) by Graham McNeill