AN : I told you this fic would have short chapters. Enjoy !
On Terra, the Angel wept bitter tears before his father's throne, and the surviving Primarchs who had kept to their oaths gathered amidst the ruins of the Throneworld. They spoke, briefly, before leaving once more – for there was much to be done. Guilliman, Dorn, Jaghatai, Sanguinius and Russ were set on pursuing the traitors and finishing them, while Lion El'Jonson wanted to return to his homeworld of Caliban, having been taunted by daemons with the knowledge that something terrible was transpiring there in his absence.
Some among the Primarchs – Russ first among them – questioned the Lion's motivations, suspicious of his desire to leave after arriving only at the last hour of the Siege. But Sanguinius and Guilliman appeased the Wolf King, telling him that they knew where Lion El'Jonson and his Dark Angels had fought during the Heresy, and that while they were sworn not to discuss it (for to do so would, inevitably, have led to the revelation of the shame that was the Unremembered Empire), the First Legion's loyalty was not in question.
At Sanguinius' demand, Vulkan alone remained on Terra, to help rebuild the Throneworld as well as to guard against any new attack from the Traitor Legions. Those few Salamanders who had survived the Heresy rallied around their Primarch, rejoicing at the discover of his resurrection, and put aside their weapons to become builders, for a time. Traumatized as they were by the depredations of the Emperor's Children, the people of Terra were now terrified of the Space Marines, seeing them as inhuman giants with no care for the lives of mere mortals – only the Eighteenth Legion was regarded differently, thanks to its warriors' selfless acts of devotion and self-sacrifice during the Siege. The charcoal-skinned, red-eyed sons of Nocturne were nearly as adored as the Angel, Sanguinius himself, was – though the Primarch of the Ninth Legion would be the first to argue that, unlike him, whom the Imperium loved for his beauty, Vulkan and his sons had truly earned the respect and adoration of the Terrans. The Salamanders were determined not to show themselves unworthy of that faith, and set themselves to the task of rebuilding.
While the loyal Legions set upon their assigned tasks, aided by the remnants of the once-mighty Imperial warmachine, the Traitor Legions fled from the wrath of the empire they had betrayed. Their flight was far from ordered : with Horus still suspended between life and death, the horde of the Warmaster broke apart, a thousand warlords and more staking their claim upon the blood-soaked Imperium. Mortal, Astartes, or other, these lords of war sought to build their own kingdom upon the ashes of the Heresy. But the loyal Legions and their allies were stronger, and over the course of the great war that would come to be known as the Scouring, they hunted each of these fell dominions and destroyed them, one by one.
The corrupted forge-worlds of the Dark Mechanicum were obliterated, the very memory of their location scourged from the archives by the data-priests, that their heresy against the Machine-God be never repeated. Systems ruled by the iron hand of Horus-sworn tyrants were freed from their masters, before the population was inspected by the newly-founded Inquisition for signs of corruption. And the worlds that were truly lost, having succumbed to the pull of Chaos and become infested with the Neverborn, were burned to ash and less than ash, banishing the daemons. Yet the true prey of the Space Marines was their own, treacherous brethren, who were also the ones who inflicted the greatest wounds upon the Imperium in those days of bitter, desperate fighting.
The World Eaters rampaged on dozens of worlds, driven by the voice of Khorne to slaughter billions in a vain attempt to ease the pain of the Butcher's Nails. They left in their wake a trail of burned-out husks before they were caught by the loyalists, and the survivors were forced into a shameful retreat that drove them into the Eye of Terror. If there was any pity left in the hearts of the loyal Legions for their renegade kin, then perhaps it was the sons of Angron who inspired it, for they were perhaps the only ones of the Chaos Marines who suffered more than their victims did.
The Emperor's Children had been among the first to flee when Horus had fallen, their ships' hulls full of billions of captives taken from Terran megacities. Their fleets scattered through the void, though all heard the call of the Youngest God drawing them toward the Eye of Terror, the place where it had been born of the Eldar's folly. Fulgrim stayed behind, however, laying an ambush for his brother Guilliman. But again the plans of a Daemon Primarch were foiled, as Sanguinius joined his brother in their hunt aboard the Pride of the Emperor. Together, the Angel and the Avenging Son destroyed the incarnated form of the White Naga, banishing Fulgrim's spirit to the Empyrean.
Mortarion and his Death Guard were the last to retreat from the fields of Terra, but the Daemon Primarch and his Plague Marines were also the first to set course toward the Eye. The voice of Nurgle pulled the Lord of Death to abandon the Materium and seek refuge within the Realm of the Gods. And so it was that the Fourteenth Legion remained one of the few to stay united as it fled from Terra and into the waiting arms of the Ruinous Powers, its hierarchy intact.
Perturabo alone managed to turn the tables of the loyalists. The Lord of Iron laid down a trap for his old rival, Rogal Dorn, and trapped him within his Iron Cage, a fortress designed to bleed the Imperial Fists Legion dry. The blood and gene-seed of thousands of Seventh Legion warriors earned Perturabo the gift of daemonhood, though he was ultimately forced to flee when Sanguinius came to deliver Dorn from the Daemon Primarch's cruel labyrinth. Even after receiving the blessing of the Dark Gods, Perturabo feared Sanguinius' power, and his decision was later proven right.
Using their sorcery, the Thousand Sons retreated to their new homeworld in the Eye of Terror, arriving well ahead of the other Traitor Legions. The sons of Magnus had joined the Siege for their own reasons, and the rebels' failure was now forcing them to reconsider their options as the plague of flesh-change spread ever further among their ranks. A long-hidden secret had also been revealed to them : that it was Horus, not the Emperor, who had ordered the destruction of Prospero, altering the orders of the Space Wolves from capture to extermination. Though Magnus' choice to join Horus had been driven by other considerations, many of his sons had hungered for vengeance, and they were shocked by this sudden revelation, left wondering what path to take now.
As the Crimson King dwelled in his Tower, pondering his options, he was blind to the treachery of one of his own. With the help of a cabal of like-minded Sorcerers, Ahzek Ahriman performed a great ritual to halt the spread of the flesh-change. He succeeded, but the Rubric, as the ritual came to be known, also destroyed the immense majority of the Legion, turning the warriors without psychic powers into dust trapped within their armor, their spirit reduced to a mere spark that could be commanded by their still-living brothers. Ahzek was banished from the Planet of the Sorcerers along with his cohorts, left to wander the Eye until they regained their Primarch's favor.