Location: A Hidden Vault Within Luna.
Luna was where mankind first touched the Cosmos. Leaving our cradle to explore the stars. It was only fitting it would be where mankind's Ascension started. In the shadows of Old Night, the newly crowned Emperor of Mankind started an impossible project within Luna. Using his own genius and the resources of newly conquered Terra and Luna, He sought to create beings that would guide mankind along the Shining Path.
The results of this great endeavor were Twenty Artificial Wombs, each containing a Fetal Transhuman greater than even anything crafted. Born of Millennia of Scientific Discovery, Warpcraft stolen from the Immaterium. and the very blood of the Anathema. These Primarchs were built to be the Heroes of a New Age. An age of Imperium. Where Humanity was ascendant and no longer feared the darkness. A noble ambition, but other forces stood in opposition to the newly crowned Master of Mankind. The Primordial Annihilator sought to claim these infant Primarchs. To warp them from paragons of mankind to tools of doom and darkness.
Reality shimmered as spacetime was distorted by a Warp Rift. The Ruinous Powers had gambled everything on this. An Immaterium Born Paradox that would seal both the Galaxy and the Anathemas Fate. Using Sons of the 17th Legion and the insanity of Warp Currents they planned to pluck the Twenty Primarchs from safety and twist them however they pleased.
Argel Tal and his brothers of the Serrated Sun Chapter exited the rift. Stunned and disjointed by the flickering visions and movements through reality Argel Tal attempted to identify his surroundings to no avail. The oily voice of Ingethel the Ascended poured into his mind. Secrets and lies were pumped into him like a serpent's venom. Like the puppets, they were the Word bearers moved forward with a stiff halting gate not known to Astartes. With their faith in the Emperor shattered fully and the Primordial Truth laid bare Tal knew what must be done.
Moving slowly past the Glass Wombs he pulled forth his blade and advanced on the Gellar Field generator at the center of the chamber. The True Gods would save the Primarchs from the False Emperor and his Father would be vindicated. In his stupor, he rose his blade and prepared to destroy the only defense the Infant Demi-Gods had from the predations of the Warp.
Right as his blade began its downward arch the Warp Stirred again. Ingethel let out a screech when she felt the power and its source. At the other end of the chamber from the Serrated Suns Portal, another gash in the Materium opened up. Not weeping corruption and Chaos like the first, this one burnt with Holy Fire. Ingethel began to quake her Daemonic form weakening under the pressure coming from the rift.
"Anathema… THE ANATHEMA HAS COME!" the newly born Daemon Prince wailed in horror and fear as the aura of the being her kind feared above all burst forth from the portal.
The Word Bearers sensed it too and as one their hackles raised at the False Emperor's presence. The pain and humiliation of Monarchia was a fresh wound in their Transhuman memories. Yet even the Word Bearers, who had been witness to the Emperor's wrath were shocked by the energy leaking from the rift. While the power unleashed on Monarchia had been far more brutal and unrestrained than the usual Psychic Aura the Emperor gave off this was far far worse. It was a Nova of sheer psychic dominion. Unfettered by mortal constraints it bathed the chamber in a white light that seared the minds and souls of the Heretic Astartes.
Ingethel buckled under the scalding light and her form evaporated like mist at dawn. With their portal collapsing and their guide cast back into the warp. The Word Bearers were lost and confused. Their Pilgrimage of enlightenment had turned into a trap. Yet the worse for them was yet to come. For this Warp Rift was not meant to banish Ingethel or protect the infant Primarchs from Chaotic taint but to transport a chosen few through time and space to avenge themselves and save the Imperium. The Legion of the Damned had come to change destiny.
Bolter fire erupted throughout the Laboratory as the Damned attacked the Word Bearers. Diving for cover the Traitor Astartes were pinned down by constant volleys of Burning Bolt Round. A number of them had been too late to react to the sudden appearance of ghostly burning Astartes and were now reduced to hunks of burning meat and bubbling blood. Recovering first Tal ordered his Battle-Brothers to open Fire on the Phantoms while avoiding the infant Primarchs.
Bolt Shells whizzed past the Gestation Capsules as the firefight continued. Alarms and Klaxon began to wail adding to the frantic chaos. Slowly but surely the Legion of the Damned moved closer and closer to the embattled heretics. Peering behind his cover Argel Tal noticed the Number on the gestation capsule one of the Damned hid behind. XIII. Struck by grim inspiration he fired his Bolt Pistol at the Womb of what would be Guilliman. Attempting to kill two birds with one shell.
Moving faster than what was thought possible for an Astartes one of the Legionaries threw himself in front of the shell. It punctured the Ghostly Astartes armor and like a candle in the wind, he flickered out of the materium. Tal's transhuman eyes noticed something particular about the martyred enemy. His armor may be burnt and blackened but the inverted Omega on his pauldron was still barely visible.
"Sons of Guilliman always willing to follow their arrogant father,"Argel said to himself before barking orders to his brothers.
"Target the Capsules marked I, VI, VII, XI, XIII, XVIII, and XIX" Tal knew his purpose here was to allow the Gods to claim the Primarchs but if he could not do that then at least he could cripple the False Emperor and eliminate threats to his father and legion before they even existed. Letting these phantoms to martyr themselves saving what might be their future gene-fathers.
Argal Tal's hypothesis was correct. Legionnaire after Legionnaire stood in front of the incoming fire to protect the infant Primarchs. Yet even with these casualties they still advanced on the Word Bearers, butchering the heretics with Bolt Fire, and blade if they got close enough to a straggling one. What had been a slaughter became a pitched a battle between the rows of Gestation Capsules
.
After ten minutes that seemed to last ten hours only a handful of Damned Legionnaires along with Tal and his three remaining brothers remained. Word Bearer Corpses and Bolter Shells littered the room while the Chambers doors quaked with the attempts of outside Imperial Forces attempting to breach the sealed room. Cursing in Colchisian Argal barked orders to his remaining Brothers. They were running out of time. Even if they won this battle the False Emperor's slaves would kill them instead.
Ordering his Brothers to retreat they charged towards the Gellar Field Generator hoping to just maybe complete their original objective. One Heretic stayed behind to provide covering fire. He screamed maddened Colchis prayers as Flaming Bolter rounds tore him to pieces. The remaining three charged towards the Generator as the Legionaries Pursued. A Volley of Bolts ripped apart another Word Bearer, but they were so close. Mere meters away from salvation and humanity's eyes being opened to the Primordial Truth.
This was not to be the case for while the firefight raged one last being exited the Legion of the Damned's portal. He now stood in between the last two Heretics and the Generator. Towering over both Astartes, with armor as burnt and blackened as the other it was still unmistakably a Custodes. With a single slash of his Burning Guardian Spear Tal's last remaining Brother was dead and he stood alone against the Black-Clad Burning Ghost of one of the Emperor's Legion.
For a split second Argal Tal and the Custodes stared at each other. Tears of Molten Metal trickled from the Custodes visor as recognition dawned upon the Serrated Suns Captains. Argal Tal's last words was "Aquillon?" As soon as those fateful words of recognition left his mouth the Guardian Spear of the Vengeful Custodes parted his head from his body.