Meros - The Red Angel: 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, he 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 forced 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 daemon-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 him 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 had conjured.The Blood Angels then completed their purge of the daemons on Signus Prime and even Kyriss the Perverse was sent screaming back to the Warp at 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. 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.