As Sub-sector Aurelia was the home sub-sector of the Chapter and the source for most of its neophytes, securing its control from assault by the forces of Chaos and various xenos was of paramount strategic importance for both the Blood Ravens and the wider Imperium.
The conflicts would lead to the corruption of a large portion of the Blood Ravens as its Chapter Master and Chief Librarian Azariah Kyras fell to the temptations of the Ruinous Power, but its Loyalist core would be reborn under the leadership of Gabriel Angelos.
First Aurelian Crusade
The Sub-sector Aurelia of the Korianis Sector had long been deeply important to the enigmatic Blood Ravens Chapter, as both a source of new recruits for the fleet-based Chapter and a major source of technology, weapons and other manufactured items drawn from its capital, the Hive World of Meridian.
At an unknown time late in the 41st Millennium, an unnamed Blood Ravens Force Commander and Sergeant Tarkus launched a deep strike onto the desert Feudal World of Calderis to aid Captain Davian Thule and his company of Blood Ravens Astartes in engaging a force of Orks who are threatening the people of Calderis.
The Blood Ravens neophytes drawn from the Aurelia Sub-sector were needed more than ever after the Blood Ravens suffered terrible losses during the campaign conducted by the Chapter in the Kaurava System. As the Blood Ravens strike force on Calderis drove away the Orks they were confronted by the Mekboy Badzappa and his Wartrukk. Although the Mek escaped, the Astartes collapsed the mine through which the Orks had been assaulting the human settlement on Calderis and claimed victory.
The Blood Ravens next attacked from the Strike Cruiser Armageddon into a hamlet on Calderis where Scout Sergeant Cyrus was waiting for them to help defend against another Ork assault. The strike force managed to fight their way to the Blood Raven commanding the defence of the hamlet, Sergeant Avitus, rescue him and save the hamlet from the Orks.
The Blood Ravens then received word that the Orks had attacked two more key locations on Calderis and they understood that someone with more tactical skill than a normal Greenskin was leading the Orks. The first attack was led by a Stormboy Nob named Skykilla and the second by the Warboss Gutrencha.
After their defeat of the Orks, the Space Marines extracted information from Skykilla and Gutrencha and discovered that both had visited the Felhammer Mine recently. They also learned that Mek Badzappa was there as well.
Sergeant Cyrus remained onboard the Armageddon to provide technical support as the Astartes strike force moved to drive the remaining Orks from Calderis. When the Astartes entered the mine they discovered an Aeldari Warp Spider Exarch and his retinue were already there but they vanished before they could be engaged, just as the Orks attacked.
The Astartes were rescued from Ork gunners by Sergeant Thaddeus. They also found Badzappa and his mob under attack by an Aeldari Warlock and a company of Guardians. Although the Astartes slew the Warlock, the wily Ork Mek escaped once again. As the Warlock died, he spoke of the existence of a greater foe that threatened all of the sub-sector, but the Blood Ravens remained unconcerned by what they took to be the random babbling of the member of a xenos race known for their duplicity.
The Blood Ravens then travelled to the jungle Feral World of Typhon Primaris to eliminate the Aeldari activity that had been detected on that world. A Warp Spider Exarch was stirring up the Feral Orks of the Evil Sunz Klan located in Typhon's jungles into revolt and he and his force had to be put down.
This Exarch mentioned nothing of the so-called "greater foe" once confronted by the Blood Ravens but Thule asked the Aeldari to return to Calderis as Mek Badzappa was launching an attack against the capital of the desert planet, and its citizens were reporting plants mutating and small purple creatures killing livestock.
The Space Marines returned to Calderis and finally killed the Ork Mek and his forces, but they were soon attacked by Tyranids drawn from a probable splinter fleet of Hive Fleet Leviathan that had entered Sub-sector Aurelia intent on devouring all of its worlds. Thule was mortally wounded by a Tyranid Warrior and Techmarine Martellus lead the Blood Ravens on Calderis back to safety after they destroyed the Tyranid attack force.
The Space Marines returned to Typhon, leaving Apothecary Gordian in charge of caring for the badly wounded Davian Thule. The Blood Ravens killed the Aeldari Ranger Nemerian, who has been stirring up trouble for the Imperium amongst the Feral Orks, and returned to Calderis to kill the Tyranid Warrior who had mortally wounded Captain Thule.
After this, the Blood Ravens were faced with three primary objectives to complete: gathering a sample of bio-toxin from the Tyranids that could be used to create a genetic poison against the splinter hive fleet assaulting Sub-sector Aurelia, securing data from an ancient Astronomical Array from the Dark Age of Technology located on Typhon Primaris that could pinpoint a critical weakness in the approaching Tyranid hive fleet, and defending the great hive city of Angel Forge on the Hive World of Meridian.
Securing the Astronomic Array granted the Blood Ravens the abilities to unleash orbital bombardments and deep-strikes, defending Angel Forge allowed Sergeant Tarkus to gain a suit of Terminator Armour, and gathering the Tyranid bio-toxin added a Dreadnought to the Blood Ravens strike force, which was actually the revived Captain Davian Thule, his body having been interred within the cybernetic coffin of the Dreadnought.
Meridian was the target of constant Aeldari attacks and it was ultimately revealed that the Farseer Idranel of Craftworld Ulthwe had been planning to lure the entire splinter Tyranid Hive Fleet to Meridian using the world's human population as bait. Then the Farseer planned to destroy it to eliminate the Tyranid threat to his Craftworld but at the expense of destroying a vital source of manufacturing for the Blood Ravens.
Upon completion of all three objectives, the Tyranid bio-toxin was ready for delivery. However, the Navigators of the Blood Ravens Battle Barge Litany of Fury, which had been making its way to the aid of the Aurelian Sub-sector for some time, were psychically assaulted by the Tyranid Hive Mind, which placed the vessel in grave danger of becoming lost in the Warp.
This effectively eliminated any potential reinforcements for the Aurelian Force Commander Aramas -- but the Hive Mind had been weakened by this exertion and sent its Hive Fleet to consume Typhon's bio-mass so that it might replenish itself.
The Blood Ravens' strike team deployed to Typhon and administered the engineered bio-toxin to the Hive Mind through its feeder tendrils. In the space battle high above the Jungle World, the Armageddon was destroyed and Apothecary Gordian was killed.
As the genetic poison took effect within the hive fleet's bioships, all appeared lost as the strike team possessed no means of retreat and massive waves of Tyranid creatures were preparing to attack. Suddenly, Captain Gabriel Angelos and an entire company of Blood Ravens landed on the battlefield from the recently arrived Litany of Fury and protected the beleaguered Aurelian Blood Ravens strike force from the oncoming swarms of Tyranids.
Angelos himself joined the Aurelian Force Commander Aramas' strike force and his aid proved decisive in killing the Hive Tyrant Alpha who was controlling the swarm. With that synapse creature dead, the Tyranid swarms became undirected by the Hive Mind and turned on each other even as the bioships in orbit fell ill and died from the bio-toxin.
The Blood Ravens had won the day and the Sub-sector Aurelia and its billions of people had been saved from complete annhilation by the Great Devourer.
Second Aurelian Crusade
Just when all seemed to be returning to normal in the Sub-sector Aurelia, the Warp opened up and spat out the former capital world of the sub-sector and ancient homeworld of the Blood Ravens Chapter, the Ice World of Aurelia.
Home to the Blood Ravens' ancient fortress-monastery of Selenon and many loyal citizens of the Imperium, the planet was corrupted by a Greater Daemon of Nurgle known as Ulkair. The Blood Ravens' Chapter Master Moriah had attempted to destroy the daemon but failed, and the weakened daemon was imprisoned in the depths of Keep Selenon by Azariah Kyras, then a Librarian of the Blood Ravens.
Yet the daemon's influence proved too strong and eventually the shaken Kyras fell to the taint of Chaos. Aurelia itself was swallowed by the Warp and its existence in the sub-sector that had been named after it was all but forgotten.
The ice-encased world returned to realspace in the late 41st Millennium bearing the foul hordes of Chaos, a warband of Chaos Space Marines from the Black Legion led by the Chaos Lord Araghast the Pillager and the former Word Bearers Dark Apostle Eliphas the Inheritor, who had been resurrected by the will of the Dark Gods so that he might seek the destruction of the Blood Ravens, now as a member of the Black Legion.
Captain Gabriel Angelos and Force Commander Aramus rallied the Blood Ravens Astartes of the 3rd and 5th Company to face this threat, but no sooner did they join combat then the Aeldari and the ever present Orks rose up to cause trouble along with the heretical soldiery of the Hive World of Meridian's noble House Vandis.
Before long the entire sub-sector was embroiled in fresh combat against multiple foes with the forces of Chaos causing havoc at will.
As the Blood Ravens scrambled to respond to these threats even more dire circumstances came to light as the space hulk Judgement of Carrion returned to the sub-sector. Determined to recover valuable intelligence and ancient advanced technology from the space hulk to aid them against the foul servants of Chaos, the Blood Ravens under the command of the local Force Commander, Sergeant Aramus, assaulted the Judgement of Carrion only to discover the bodies of fallen Blood Ravens from the 5th Company, formerly members of an expedition led aboard the Space Hulk by Apothecary Galan.
As the forces of Aramus investigated the hulk they were shocked to find evidence of Galan's corruption by the powers of Chaos, but the truth of the matter was far more insidious.
As Aramus and Captain Angelos desperately fought to keep control of the sub-sector and unlock the secrets of both the Judgement of Carrion and the lost planet Aurelia, they were interrupted by the arrival of Apollo Diomedes, the Captain of the Blood Ravens Honour Guard and the right hand of the Blood Ravens' Chapter Master and Chief Librarian Azariah Kyras. Diomedes ordered all Blood Ravens forces to stand down, an order both Angelos and Aramus promptly ignored.
As Diomedes got increasingly sterner in his orders, Aramus and Angelos continued to resist the forces of the Black Legion, with whom the Chapter had recently avoided open conflict for an unknown reason.
As his investigations continued, Aramus discovered to his horror that the source of corruption was none other than Chapter Master Kyras himself, who had fallen under the sway of the Greater Daemon Ulkair during his earlier campaign on Aurelia centuries before and spread his taint to Galan aboard the Judgement of Carrion.
Kyras escaped the doomed world of Aurelia aboard the Space Hulk and had returned to the Chapter with his dark seed of corruption when he met with Galan's expedition.
Daring open conflict with Captain Diomedes' forces in their base-camp on Calderis, Aramus attacked Galan, slaying the Traitor and his tainted bodyguard of Terminators, a battle which ended in a confrontation with Captain Diomedes himself.
Reluctant to accept the corruption of his political patron within the Chapter, Diomedes found himself torn but let Aramus and his comrades leave Calderis and continue their operations against the Black Legion warband of Araghast the Pillager. The Battle of Aurelia culminated in the death of Eliphas the Inheritor, who seized control of the Black Legion warband by betraying Araghast and leaving him to the mercies of the Blood Ravens earlier in the fighting.
Despite Eliphas' machinations, Aramus was able to re-seal the Daemon Ulkair in its icy tomb within Keep Selenon on Aurelia. Even with this victory, Chapter Master Kyras declared Captain Gabriel Angelos a Renegade and Traitor to the Chapter and Sergeant Aramus found himself faced with the knowledge that the Chapter Master was a corrupt agent of the Chaos Gods.
Diomedes and Aramus returned to the Chapter to bide their time, while Angelos fled Kyras' wrath. When the time was right the 3rd Company was determined to return and join with Force Commander Aramus and Captain Diomedes to cleanse the Chapter of the insidious taint that lay like a malignant cancer at its core.
Third Aurelian Crusade
This third and final campaign in the Aurelian Sub-sector took place ten standard years after the banishment of Ulkair. Despite the banishment of the Greater Daemon of Nurgle and the defeat of the Black Legion, the worlds of the Aurelian Sub-sector remained gripped by constant warfare and bloodshed.
More Black Legion forces and Chaos Cults arose to cause havoc throughout the sub-sector, while Imperial forces struggled with the feral remnants of the Tyranid invasion, and Orks continued to ravage the fringes of every world. The Aeldari still raided from the shadows, whispering of the remains of a long-fallen Craftworld.
In this situation, the Imperium had finally reached the limits of its patience. In a bold effort to restore full control over the sub-sector, Imperial Segmentum Command sent several regiments of the Cadian Shock Troops of the Astra Militarum to the sub-sector, led by the Ordo Hereticus Inquisitor Adrastia, who had been tasked with conducting an investigation of the Blood Ravens and determining whether they had been hopelessly corrupted by the Archenemy.
She was to make her determination before the arrival of a large Ordo Malleus Retribution Fleet, which was ordered to subject every inhabited world in the sub-sector to Exterminatus if the corruption was deemed to run too deep.
The Imperial Guard forces quickly took control of the sub-sector's various Planetary Defence Forces. The bulk of these troops had been deployed to Typhon Primaris, a world whose dense jungles provided sanctuary to both aliens like Orks and Tyranids as well as Heretics.
However, progress was slow, and the Imperium was increasingly ready to unleash the fires of Exterminatus. But the recently arrived Imperial forces under Adrastia's command actually did more harm than good in the end, as hundreds of Guardsmen fell victim to the whispered temptations of the Ruinous Powers, causing dissension within the ranks.
Having uncovered heresy in the highest ranks of his Chapter, Blood Ravens Captain Gabriel Angelos had been branded as a Traitor by his corrupt Chapter Master Azariah Kyras. Unwilling to spill the blood of his brother Space Marines, Gabriel had gone into hiding.
There, he gathered what few friends and allies he could, readying himself to oppose the Chaos taint that consumed his brothers. Unable to confront Azariah Kyras directly, the now-Renegade Captain Angelos was forced to rely on those men still loyal to him to help prove that their current Chapter Master was corrupted by Chaos and was the true Traitor.
Later, Angelos and his Renegade Blood Ravens determined to eliminate Azariah Kyras once they learned that he planned to use the impending Exterminatus action of the sub-sector by the Ordo Malleus Retribution Fleet as a sacrifice to Khorne and ascend to daemonhood. Unfortunately for Angelos, Captain Apollo Diomedes still believed that Chapter Master Kyras was loyal.
During the beginning of the campaign, Diomedes, Techmarine Martellus and a respected Veteran Space Marine Sergeant known only as "The Ancient," who was in fact the former Sergeant Tarkus, fought their way across Typhon to root out and eventually destroy the Black Legion Chaos Lord Eliphas the Inheritor, resurrected once more by his dark patrons.
Diomedes and his Blood Ravens attempted to reach a means of transport off Typhon while escaping the clutches of a local Chaos Cult and Traitor Imperial Guardsmen along the way. Arriving on the world of Calderis, the Blood Ravens fought against their corrupted battle-brothers who were loyal to Kyras, successfully preventing them from purging the planet of all human life.
After next destroying a Warp portal on the former sub-sector capital world of Aurelia, Diomedes learned of an attack on the Hive World of Meridian by Traitor Guardsmen and arrived there with his forces.
The Blood Ravens succeeded in killing the Traitor Guardsmen present on Meridian and uncovered a transmission from Kyras that not only revealed his location on Typhon, but also finally convinced Diomedes that Kyras had been corrupted by Chaos. Diomedes and his Astartes returned to Typhon Primaris to confront Kyras directly, only to be ambushed by a war host of Asuryani from Craftworld Biel-Tan.
Wary of a seemingly sorcerous ritual the Aeldari were carrying out, Diomedes and his Space Marines slew the Aeldari present there. Following this action, Kyras revealed that the Aeldari ritual was actually preventing the Imperial Inquisition Retribution Fleet from arriving at the sub-sector through the Warp.
The Inquisition fleet then made the jump into the sub-sector from Warpspace, and initiated the expected Exterminatus action on Typhon Primaris. Diomedes and the Loyalist Blood Ravens escaped Typhon before the Exterminatus was complete, but the once verdant jungle world of Typhon Primaris was reduced to ash.
Finding themselves on the Space Hulk known as the Judgment of Carrion, the Loyalist Blood Ravens recovered and determined to stop Kyras once and for all. It was deduced that the Traitor Chapter Master was hiding on the Dead World of Cyrene, Angelos' own lost homeworld.
As Cyrene had undergone an Exterminatus action of its own at the order of Gabriel Angelos many solar decades before, the Inquisition's Retribution Fleet had no reason to travel there. On Cyrene, Angelos and his Blood Ravens launched an attack against a joint alliance of Black Legion Chaos Space Marines, corrupt Imperial Guardsmen and Traitor Blood Ravens.
Kyras began his ascent to daemonhood as the battle unfolded, drawing on the power created by the sacrifice of billions across the sub-sector as the Inquisition's genocidal actions proceeded. Gabriel and his 3rd Company, supplemented by Terminators of the elite 1st Company, launched an attack on Kyras but were quickly wounded or killed.
But the group of Loyalist Blood Ravens under the command of Diomedes then launched their own attack, which succeeded in killing Kyras just as his powers as a newly-ascended Daemon Prince emerged.
Diomedes immediately contacted Inquisitor Adrastia and requested that she halt the Exterminatus of the Aurelian Sub-sector since the source of the Chaos taint had been eliminated. The Blood Ravens Chapter was subsequently purged of any remaining Chaos stain, its corrupted battle-brothers eliminated with a bolter shot to the head.
For his loyalty to the Emperor and consistent leadership through the myriad crises of the Aurelian Crusades, Angelos was elected the Blood Ravens' new Chapter Master by acclamation.