It had been five years since the events now known as the Crusade of Plague, a campaign recorded in the archives of both the Inquisition and Camelarion.
Many of the specific details surrounding the crusade had, of course, been redacted. Some were removed to preserve the morale of the masses. Others were sealed away to ensure that those who might one day read the records would not be exposed to knowledge that could lead to corruption.
Among the many details omitted from the official records was the message given to Atharion.
No one knew what the message contained.
When Atharion viewed it, he had ordered that the chamber be cleared. No one had been present when he read the final words of the former Grand Master of the Sanguine Wardens.
Whatever Atharion had seen within that data-crystal, it had changed everything.
The first order he gave upon leaving the chamber was to assemble a strike force and prepare it for immediate deployment to Segmentum Obscurus.
Its mission was known to no one.
Not even the members of the Twelve or the Round Table were given the full details.
The only information made available to them was the composition of the force.
Five Argent Wardens.
Fifty Terminators drawn from the 1st Company.
Fifty Astartes from the 2nd Company.
One hundred Astartes from the 5th Company.
Alongside them would travel five Librarium detachments, each commanded by a Master of the Librarium.
Three Apothecarion detachments.
Two Armoury detachments.
And five Reclusiam detachments.
It was an unusually large force for a mission whose purpose remained completely classified.
The fleet assigned to it was equally extraordinary.
One Ramilies-class Star Fort.
Five Battle Barges.
Ten Strike Cruisers.
Together, they formed a fleet powerful enough to wage a campaign against an entire world.
Yet no campaign had been declared.
No enemy had been named.
No destination had been announced beyond the vastness of Segmentum Obscurus.
Officially, the force did not exist.
Its deployment was buried beneath layers of classification within the archives of Camelarion, accessible only to Atharion.
And for five years, no one had asked Atharion what he had seen upon that data-crystal.
Perhaps because they feared the answer.
Or perhaps because, deep within themselves, they already understood that whatever had been written there was something that the former Grand Master of the Sanguine Wardens had died trying to reveal.
A secret that too important to know by a handful, or in this case, only one person.
But, another more direct reason that they not asking anything about them is because the battle reports come from the strike group.
For five years, the strike group had operated throughout Segmentum Obscurus, and in that time, it had accumulated an impressive list of battle honours.
Chaos warbands destroy or chase back to the Eyes.
Ork Waaagh! stopped with surgical assault that kill their Warbosses.
Cult uprisings had been crushed before they could possed a serious threat.
The strike group had suffered losses, but never enough to threaten its ability to continue the campaign. Its Battle Barges and Strike Cruisers returned from each engagement scarred and battered, only to be repaired and sent back into the darkness.
And every time they returned, they brought another victory.
To the members of the Twelve and the Round Table, the explanation seemed simple.
Atharion had discovered something during the Crusade of Plague—something dangerous enough to warrant a secret expedition into the Segmentum Obscurus.
Whatever it was, the strike group had apparently dealt with it.
There was no reason to question a successful campaign.
So, for these five years, that strike group is the only major campaign that the Dark Knights is doing as Atharion keep the whole Chapter in Camelarion.
As to the reason, the training of the newly founded sucessor Chapters.
After a meeting with the Twelve and later the Round Table, Atharion commence the founding of thirteen new Chapters.
Each of the Chapters was assigned to one of the Thirteen Gates, further reinforcing the already heavily fortified fortress worlds that protected the core worlds of Camelarion.
The first of these Chapters was the Wardens of the First Wall, assigned to Loarre, the first of the Gate Worlds to complete its colonization and the construction of its great fortress complexes. The Chapter was entrusted with guarding the first defensive line of Camelarion and ensuring that no enemy could penetrate beyond the outermost Gate.
The Knights of the Eastern Gate were assigned to Antioch, a Gate World controlling a major Warp route that linked the core worlds with the eastern regions of Camelarion and the neighboring sectors. Its position made it one of the most important gateways for both military movement and trade.
The Scarlet Castellans were assigned to Acre, a heavily fortified Gate World positioned along one of the principal approaches toward the core. Its fortifications were designed to withstand prolonged sieges, while the Chapter itself was tasked with ensuring that any enemy attempting to force its way through the Gate would be met by a wall of Astartes.
The Knights of the Rose were assigned to Rhodes, another strategically positioned fortress world guarding a major approach into Camelarion. Its orbital defenses and planetary fortifications made it an important strongpoint within the defensive network.
The Unbroken Knights were assigned to Malta, a fortress world whose extensive defenses controlled one of the principal routes leading deeper into the realm. Its Chapter was expected to hold the Gate regardless of the strength of the enemy attacking it.
The Swords of Avalon were assigned to Rouen, a heavily fortified Gate World protecting a vital route toward the inner territories of Camelarion. Its position allowed the Chapter to respond quickly to threats approaching from several directions.
The Citadel Guard were assigned to Aleppo, a fortress world positioned along another major strategic approach. Its vast defensive complexes were constructed to slow and destroy invading forces before they could reach the more valuable worlds beyond it.
The Knights of High Keep were assigned to Königstein, whose immense citadels dominated the surrounding landscape. The Gate World was designed as a fortress within a fortress, with successive defensive lines intended to continue resisting even after its outer walls had fallen.
The Knights of Prague were assigned to Prague, another strategically important Gate World whose fortifications protected one of the major routes toward the Camelarion core. Its Chapter was tasked with defending both the world and the Warp route passing through its territory.
The Knights of High Rock were assigned to San Leo, a heavily fortified world built around a formidable natural stronghold. The combination of its terrain and artificial defenses made it one of the more difficult Gates to assault directly.
The Knights of the Grail were assigned to Chevaliers, a fortress world where the influence of its ancient feudal society remained particularly strong. The people of Chevaliers retained many traditions of knightly nobility, and the arrival of an Astartes Chapter bearing such traditions only strengthened the relationship between the Chapter and its population.
The Wardens of the Narrow Path were assigned to Calais, the Gate World responsible for protecting the most unstable Warp route among the Thirteen Gates. The route was notoriously unpredictable, with sudden fluctuations and dangerous Warp phenomena making navigation difficult even during relatively peaceful periods. The Chapter therefore maintained a constant watch over the passage, ready to respond to anything that emerged from it.
Finally, the Knights of the Lion Keep were assigned to Gaillard.
Of the Thirteen Gates, Gaillard held the most prestigious strategic position.
A major Warp route passed through the system, directly linking Camelot with the northern regions of Camelarion. Whoever controlled Gaillard therefore possessed control over one of the most important routes connecting the heart of the realm with its northern territories.
Yet despite its importance, Gaillard was the last of the Thirteen Gate Worlds to complete its construction.
Its enormous fortress network, orbital defenses, void docks, and Warp-route infrastructure had taken longer to complete than those of the other Gates. By the time the world was finally ready to receive its Chapter, the other twelve Gate Worlds had already established themselves as bastions of Camelarion.
For that reason, the Knights of the Lion Keep were given a position that carried enormous prestige, but also an equally enormous responsibility.
The Thirteen Chapters were not merely successor Chapters created to increase the number of Astartes defending Camelarion.
They were the guardians of the realm's outer wall.
So, to ensure that each Chapter was properly prepared for its duty, Atharion tasked the entire Dark Knights Chapter with their training.
Now, after five years, Atharion begin to send the Dark Knights with elements from the Shield Chapters accompany them so that they can have real combat experience from fighting the xenos, traitors and cultists other than the combat simulation that they doing on the Gate worlds.
===
723.M36
For almost four hundred years, Atharion had rarely left Camelarion, and he had almost never left Avalon, the fortress-monastery of the Dark Knights.
His absence from the wider galaxy had not been caused by cowardice, nor had it been due to a lack of enemies.
It had been a choice.
For centuries, Atharion had buried himself beneath mountains of administrative work, overseeing the reconstruction and stabilization of the central regions of Camelarion.
Worlds had to be rebuilt.
Trade routes had to be restored.
Military forces had to be reorganized.
New fortifications had to be constructed.
But now, in 723.M36, that period was coming to an end.
The restoration of the region that effected by the Crusade of Plague have already enter a stable progression.
And, Atharion remember an important event that will happen this year.
The 5th Black Crusade, the crusade where Abaddon the Despoiler try to summoned the Daemon Prince Doombreed and destroyed two Chapters of Space Marines in the process. Another than this, this also where the Astral Claws earn the honor to have their Chapter Standard was placed in the halls of the Eternity Gate in the Imperial Palace on Terra.
With this in mind, the Dark Knights once again began to mobilize.
It was the first major mobilization of the Chapter since the conclusion of the Crusade of Plague.
Atharion had no intention of allowing Abaddon to accomplish any of his objectives during the Fifth Black Crusade. If the Despoiler intended to unleash another catastrophe upon the Imperium, then the Dark Knights would be there to oppose him.
But the Dark Knights would not go alone.
Atharion summoned the Star Chasers and Star Seekers, ordering both fleet-based Chapters to prepare their vessels for immediate deployment. Their ability to operate independently in the void made them particularly valuable for the campaign, allowing them to scout ahead of the main force, intercept enemy fleets, and respond to threats that the larger Imperial formations might be too slow to reach.
The Knights of the Lion Keep were also called upon.
As guardians of Gaillard and the most strategically important Warp route among the Thirteen Gates, their deployment represented a significant commitment. Yet Atharion considered the risk acceptable. The Knights had now accumulated sufficient experience through their training deployments, and their absence would not leave Gaillard undefended.
The Swords of Avalon were likewise ordered to prepare for war.
Together, these Chapters would form the core of Atharion's expeditionary force.
But Atharion did not intend to rely solely upon the Astartes.
A request was also sent to Legio Solaria.
The Titan Legion had become one of the most valuable military assets within Camelarion, and Atharion wanted them beside him when the Dark Knights went to war against the forces of the Despoiler.
Legio Solaria had been granted an industrial world named Apollo as its new home following the agreement Atharion have with them. The Archmagos who had survived the catastrophe was appointed governor of the world, allowing the surviving Mechanicum leadership of Tigrus to establish a new foundation for the Legion.
Atharion had provided them with considerable resources during the rebuilding.
Titan components.
Weapons.
Ammunition.
Forge machinery.
And, most importantly, new God-Machines to replace those that had been lost.
He had also granted the Archmagos permission to transform Apollo from an ordinary industrial world into a fully fledged Forge World.
The intention was not merely to provide Legio Solaria with a permanent source of replacement parts and ammunition.
Atharion wanted Apollo to become another pillar of Camelarion's military-industrial power.
A world capable of producing weapons, vehicles, Titans, and other war materiel for the realm, while also ensuring that Legio Solaria would never again be dependent upon distant Forge Worlds for its survival.
Over the years, the investment had begun to bear fruit.
The Legion had slowly rebuilt itself.
The manufactorums of Apollo worked without rest, producing new weapons and armor while the surviving Titan crews passed their knowledge to newly raised Princeps and Moderati.
By 723.M36, Legio Solaria had recovered a considerable portion of its former strength.
Twenty Warlord Titans.
Twenty-three Reavers.
And twenty-one Warhounds.
Atharion wanted to see whether the Legion had truly retained the quality it possessed before the destruction of Tigrus, or whether its rapid reconstruction had come at the expense of the experience and discipline that made a Titan Legion truly formidable.
Numbers alone did not make a Legio.
A newly constructed God-Machine could possess the same weapons and armour as one that had fought for centuries, but its Princeps had yet to develop the instincts necessary to command such an engine. The same was true for the Moderati, Tech-Priests, and countless others who formed the soul of a Titan crew.
The Fifth Black Crusade would provide the answer.
As for Legio Argentum Fulgur, Atharion decided that the Silver Lightning would remain within Camelarion.
Nine had already begun preparations for his own crusade.
An Ork empire was growing dangerously close to the realm's borders, spreading across approximately six systems. The greenskin population had grown beyond the point where ordinary Imperial forces could reasonably contain it, and its warbands were beginning to display the signs of a much larger Waaagh! gathering around them.
Atharion had been aware of the threat for some time.
He could have ordered its destruction before it reached its current size.
Nine, however, had asked him not to.
The Fabricator-General of Thoros
wanted his Order Dominus to experience a genuine campaign.
Not a training exercise.
Not a simulated engagement.
A real war against an enemy that could not be predicted or controlled.
Atharion had reluctantly agreed.
The danger was considerable, but Nine's reasoning was sound. If the Order Dominus were ever expected to command forces independently, they needed to experience the realities of war other than simulations and the records that they consume in their data-vault.
Thus, Legio Argentum Fulgur remained in Camelarion while Nine prepared his crusade.
There was another reason Atharion was willing to leave the Silver Lightning behind.
The Legion had already suffered losses during the Crusade of Plague.
One of the worst battles had taken place upon Thoros, a major Forge World located in the south-eastern regions of Camelarion.
During the Crusade, a large Dark Mechanicum force had launched an assault upon the system.
The Thoros defence fleet had been engaged almost immediately by the traitor warships, keeping the Imperial vessels occupied while the main enemy force began its planetary assault.
The attackers were not merely Dark Skitarii.
Among their forces were Titans of Legio Vulturum, allowing the traitors to deploy God-Machines alongside their ground forces.
The battle for Thoros had been brutal.
The planetary defence forces fought desperately to prevent the traitors from reaching the primary forge complexes, while the Titan Legions fought among the vast manufactorums and industrial districts.
Thoros ultimately survived.
The traitors were eventually defeated, and the other worlds within the system remained protected.
But victory had come at an enormous price.
The main Forge Temple survived.
So did the two Fortress-Temples.
The Titan construction yards also remained operational, although heavily damaged.
Almost everything else was destroyed.
One after another, the lesser Forge Temples of Thoros were reduced to burning ruins.
Entire manufactorum districts were lost.
Thousands of Tech-Priests and Skitarii were killed or simply vanished during the fighting.
For Nine, however, the destruction of Thoros represented something far greater than the loss of infrastructure.
Almost a decade of his work rebuilding the Forge World had been reduced to ash in a single battle.
He had spent years restoring its manufactorums, recovering ancient machinery, rebuilding its industrial capacity, and transforming Thoros into one of the great pillars of Camelarion's Mechanicus infrastructure.
Now, much of it was gone.
Yet the scale of the traitor assault was not what disappointed Nine most.
It was the performance of the Order Dominus.
The Order had been created with an enormous advantage that few other military organizations within Camelarion possessed.
Nine had accumulated an immense collection of battle records, some dating back to the earliest days of the Great Crusade and continuing through the end of the Horus Heresy.
Every Tech-Priest inducted into the Order Dominus was given access to these records.
They studied the campaigns of the Legiones Astartes.
They studied the tactics of the Imperial Army.
They studied the doctrines of the Mechanicum and the strategies employed by ancient Titan Legions.
They had access to records documenting sieges, planetary assaults, void engagements, armoured warfare, counter-insurgency operations, and countless other forms of warfare.
In theory, they should have been among the most knowledgeable military commanders within Camelarion.
They knew how wars had been fought for thousands of years.
They knew what strategies had succeeded.
They knew which tactics had failed.
They could identify the weaknesses of an enemy formation simply by studying its deployment.
But there was one thing those records could not provide.
Experience.
The Order Dominus understood war intellectually.
They did not understand it instinctively.
They had never experienced the confusion of a battlefield where communications failed and plans collapsed within minutes. They had never commanded forces while watching their carefully constructed formations disintegrate under unexpected enemy fire. They had never been forced to make decisions with incomplete information while knowing that a wrong decision could cost thousands of lives.
They had studied war.
They had not lived through it.
And when the Dark Mechanicum attacked Thoros, that distinction became painfully apparent.
And so, this is the reason why Nine wanted that Ork domain to survive, so that he can throw the the members of Order Dominus into a war that they can gain really experience.
After two weeks of preparing the expedition force, Atharion finally lead the fleet from Camelot and towards where the Fifth Black Crusade will happen
Elysia Sector.