Siege of Vraks

Herein follows an examination of the most lamentable Siege of Vraks, bastion and Armoury World of his most Divine Emperor, of the plans of those treacherous and heretical rebels that led to its downfall and the glorious sacrifice of the Emperor's Imperial Guard among the grim and hardy regiments of Krieg, and those misguided Mortals who have unwittingly venerated the Powers of Chaos, at a terrible cost in blood, but worst still - to the eternal damnation of their own souls. - Inquisition report on the Siege of Vraks

The Siege of Vraks was an Imperial miltary campaign fought over the course of 17 standard years to retake the Imperial Armoury World of Vraks Prime from the heretical Forces of Chaos led by the Apostate Cardinal Xaphan. Vraks was besieged by the forces of the Imperium of Man in 813.M41, after the attempted assassination by an agent of the Officio Assassinorum of the heretical and traitorous Cardinal-Astra of the Scarus Sector, Xaphan, failed. The Imperial Guard's 88th Siege Army was raised from line regiments of the Death Korps of Krieg to undertake the siege of Vraks and bring the renegade cardinal down in a campaign of attrition that the Administratum's Adepts calculated would take 12 standard years to successfully conclude. Overall command of the army and the Vraksian Campaign was given by the Imperial Guard's Segmentum Obscurus Command to Lord General Zuehlke, the son of a well-connected Imperial noble family from Segmentum Solar, who maintained his campaign headquarters on Thracian Primaris. The Zuehlke family's influence stretched across the higher echelons of the Imperial Navy and the Imperial Guard. His great-grandfather had once served as an attache to the Lord Commander Solar on Terra. Lord Zuehlke's qualifications for leading the campaign, apart from his social rank, were few beyond his martial upbringing and a detailed study of the Tactica Imperialis, but political pressure and a good family name yielded its rewards. At the conclusion of what actually turned out to be a 17-year-long Imperial campaign of attrition requiring 34 Regiments of the Imperial Guard to re-take the planet in 830.M41, 14 million Imperial Guardsmen had been lost and Vraks Prime's entire original population of 8 million souls had been consumed in the violence or exterminated after they fell to Chaos corruption. The world was then declared dead by the Imperium and placed under an interdiction to cordon it off from the rest of human space as ordered by the Ordo Hereticus' Inquisitor Lord Hector Rex.

History
"When the maelstrom descends, Vraks shall overflow with blood and skulls, and even the dead shall find no peace. Millions shall be sacrificed in their names, and the true Gods will rejoice...I have seen it, for I am the messiah of the coming apocalypse." - Lord Xaphan, Apostate Cardinal-Astra of Scarus, Arch-Heretic and the Despot of Vraks

After the previous Cardinal-Astra Borja of the Scarus Sector in Segmentum Obscurus died in 804.M41 following 400 standard years of life greatly extended by the ministrations of the Adeptus Mechanicus' Magos Biologis, his successor, Cardinal-Astra Scarus Xaphan, took his place as the Cardinal of the Scarus Sector. Over the course of 5 years, Xaphan undertook a pilgrimage across the Scarus Sector, his new domain. He wished to see the places he would preside over, and he wished to bring a spiritual revival to the people. Where he and his entourage passed, he amassed ever more followers in a series of religious uprisings. Criminal governments and oppressive tyrannies were shattered with each world he traveled to. Whispering into his ear was the Cardinal's favoured advisor, Deacon Mamon, a secret devotee of Chaos, who pushed the Cardinal into believing himself to be a sacred champion of the Emperor of Mankind, who would single-handedly reignite the faith of the people of the Imperium and lead them to new heights of righteousness. After years of pilgrimage, during which he was increasingly received as a living saint by the people of his sector, Xaphan went into seclusion on the Imperial Armoury World of Vraks in 809.M41, also the site of a popular Imperial Cult shrine of Saint Leonis the Blind, an Ecclesiarchy missionary who had been martyred in the 38th Millennium after having his eyes removed while spreading the word of the Imperial Creed across the less civilised worlds of the Scarus Sector. A shrine had been built to contain the saint's remains and relics, as well as a palace for the Cardinal-Astra of Scarus should he ever chosoe to make a pilgrimage to the shrine. Here, Xaphan chose his battlefield. As the Cardinal had come to hold, through Deacon Mamon's careful encouragement, that corruption was eating away at the Imperium, he now saw himself as a messianic figure destined to ignite a holy war and give the faithful a chance to purge the galaxy of darkness. Believing the Cardinal to be amassing far too much popularity and power, an agent of the Officio Assassinorum was sent by the Ordo Hereticus of the Inquisition to assassinate Xaphan during one of his sermons. After the failed attempt on his life by this operative, the Armoury World of Vraks erupted in full-scale rebellion against the Imperium. It wasn't long until the Citadel and the industry of the armoury world were under Xaphan's control. By seceding Vraks from the Imperium, Imperial forces in the sector and, in some cases, the entire Segmentum, would be left without adequate resupply of arms and armour. By breaking the Imperial supply chain of which Vraks was a part, forces as far removed and important as the Cadian Imperial Guard Regiments guarding the Eye of Terror would be sparsely armed, allowing a potentially major Chaos incursion to occur in or around the Cadian Gate. The Administratum deemed that Vraks must be returned to the Imperium's fold. By the time word reached the Imperium of the rebellion on Vraks, it was already too late. Millions of Traitors and heretics were now dug into meticulously planned, constructed, and reinforced defences, with massive orbital lasers protecting the world's Citadel from orbital bombardment and assault. It fell on the Imperial Guardsmen of the Death Korps of Krieg, united under the umbrella of the Imperium's 88th Siege Army, to dislodge the traitorous forces of Cardinal Xaphan in what would become a grinding war of attrition that would consume millions of lives across 17 standard years of battle.

Background to Conflict
"The Scarus Sector is a tinderbox - one spark may soon become a great conflagration. I shall light the fires." - Xaphan, Cardinal-Astral Scarus

After the previous Cardinal of the Scarus Sector in Segmentum Obscurus died, his successor, Cardinal Xaphan, took his place as the Cardinal-Astral of the Scarus Sector. Over the course of many years, Xaphan undertook a pilgrimage across the Scarus Sector, his new domain. He wished to see the places he would preside over, and he wished to bring a spiritual revival to the people. Where he and his entourage passed, he amassed ever more followers in a series of religious uprisings. Criminal governments and oppressive tyrannies were shattered with each world he travelled to. Whispering into his ear was the Cardinal's favoured advisor, Deacon Mamon, a secret devotee of Chaos. After years of pilgrimage, Xaphan went into seclusion on the Imperial Armoury World of Vraks Prime, also the site of a popular Imperial Cult shrine dedicated to Saint Leonis the Blind. Here, Xaphan chose his battlefield. Believing that corruption was eating away at the Imperium, he thought himself a messianic figure destined to ignite a holy war and give the faithful a chance to purge the galaxy of darkness. Believing the Cardinal to be amassing far too much popularity and power, an agent of the Officio Assassinorum was sent by the Ordo Hereticus of the Inquisition to assassinate Xaphan during one of his sermons. After the failed attempt on his life by this operative, the Armoury World of Vraks erupted in full-scale rebellion against the Imperium. It wasn't long until the Citadel and the industry of the armoury world were under Xaphan's control. By seceding Vraks from the Imperium, Imperial forces in the sector and, in some cases, the entire Segmentum, would be left without adequate resupply of arms and armour. By breaking the Imperial supply chain of which Vraks was a part, forces as far removed and important as the Cadian Imperial Guard Regiments guarding the Eye of Terror would be sparsely armed, allowing a potentially major Chaos incursion to occur in or around the Cadian Gate. The Administratum deemed that Vraks must be returned to the Imperium's fold. By the time word reached the Imperium of the rebellion on Vraks, it was already too late. Millions of Traitors and heretics were now dug into meticulously planned, constructed, and reinforced defences, with massive orbital lasers protecting the world's Citadel from orbital bombardment and assault. It fell on the Imperial Guardsmen of the Death Korps of Krieg, united under the umbrella of the Imperium's 88th Siege Army, to dislodge the traitorous forces of Cardinal Xaphan in what would become a grinding war of attrition that would consume millions of lives across 17 standard years of battle.

Preparations
The Imperium preparations for the Siege of Vraks were simple: how many men had to die before the world could be retaken? The Imperial forces had to overwhelm the Apostate Cardinal's defence lines, destroy his planetary defence batteries and then eventually storm and capture the Vraksian Citadel and starport, all operations where losses could be reduced to a simple mathematical formula. Everything in the 88th Siege Army was to be an expendable resource. The campaign for Vraks would be the most impersonal kind of warfare. Within the Death Korps of Krieg Regiments that would make up the totality of the 88th Siege Army, the men were not named, just numbered, so that they could be quickly tallied-up and counted off lists, whether for supplies or burial. The regiments would be ordered into combat already essentially knowing how many of their number were expected to die to secure their objectives. The lives of the Krieg Guardsmen were no more important than the daily fuel consumption rates of their vehicles or the expenditure of artillery shells. They were also expected to win the campaign in exactly 12 standard Terran years.

On Vraks Prime after the Cardinal's seizure of the world, the sudden uprising and the Apostate Cardinal's victory had escalated into an unexpected surge of mob violence. For several months the heretics fought amongst themselves to establish a new power structure centred on the Cardinal. New leaders emerged from the Vraksian Planetary Defence Force garrison and the Departmento Munitorum penal labour corps. Those who probed their loyalty to the Cardinal's new regime were rewarded with positions of power over their fellows. The very best of these men were inducted into the ranks of the elite Disciples of Xaphan, the heart of his new Chaos Cult, or given roles as Enforcers--essentially the Apostate Cardinal's cadre of brutal strongmen who served as officers and oversaw the rank and file, enforcing obedience and discipline through any means necessary, and the more brutal the better. After the rioting and bloodshed had ended, the Cardinal's commanders set about their first task--to defend Vraks from the Imperium's expected assault. They had to prepare their men and train an army. They had vast quantities of Imperial Guard supplies to plunder. Their army would be well-equipped and occupy very strong defensive positions, but they still had to be prepared for whatever the Imperium's armed forces would throw at them. The Cardinal issued instructions that Vraks Prime should be turned into a slaughterhouse and that no defender could expect any mercy from the Imperium, so they must fight or face execution by the enemy. Only by defeating the Imperial enemy could any man on Vraks expect to survive. For those that fought well thete would be great rewards. For those that failed in their duty to the Apostate Cardinal, there would be summary execution at the hands of Xaphan's corps of Enforcers. After the uprising the Traitors' newly won freedom was short-lived. The labourers of the Departmento Munitorum were soon put back to work for their new master, improving the Citadel's defence lines, moving minefields or laying new ones and rolling out miles of razorwire. Artillery crews practiced ranging shots while the Vraksian Traitor Militia, whether willing combatants or forced into service, were trained with their newly looted weapons, mostly standard-issue Imperial Guard Autoguns. The Apostate Cardinal's Traitor army was well-prepared. When it came, the battle would be hard fought and very bloody.

The Vraksian Traitor Militia was formidable force, primarily due to its sheer size. Althugh no exact figures remain available, it was believed that the population of Vraks Prime was some 8,000,000 people and all of them now had to be considered Traitors and manpower for the Apostate Cardinal's army. Quality varied greatly in the militia, from well-trained and well-equipped troops who possessed fanatical morale to an undiscipline mob of half-trained conscripts. The best Vraksian troops were the Disciples of Xaphan. This elire cadre of troops were the Cardinal's own men, hand-picked by his Ecclesiarchical represetatives for their loyalty to him and many had prior military experience. All had sworn oaths of service to the Cardinal himself and in return they had the pick fo Vraks Prime's plunder. The Imperium had no idea how many Disciples Xaphan had, but they would form the disciplined core of his Traitor Militia.

After the Disciples of Xaphan in quality, there was the original Vraksian planetary garrison's auxilia. Due to its strategic importance, Vraks Prime had been guarded by a large force of garrison auxilia. These troops were equivalent in quality to a well-trained Planetary Defence Force (PDF), the Imperium's standard reserve forces for the Imperial Guard Regiments. These auxilia did not have the training or equipment of regular Imperial Guardsmen, but access to the Departmento Munitorum stores on Vraks rectified any equipment deficiences and provided vast numbers of heavy vehicles such as Leman Russ main battle tanks, Chimeras and Basilisks. The auxilia's fighting strength had been built around a backbone of veteran Imperial Guardsmen and officers drawn from disbanded regiments. Though now well-equipped, the Imperium believed it unlikely the garrison forces could do more than man a static defensive line.

The Traitor Militia's next group of troops were drawn from the Vraksian labour corps. The Departmento Munitorum maintained a labour corps on Vraks Prime that was large and included many Ogryns. The labour corps was made up of indentured workers who did routine labour like constructing and repairing roads, pouring the ferrocrete for new bunkers, digging out new underground storehouses and transporting goods and equipment to and from the planet's only starport. Most were downtrodden souls with little left to hope for in life other than endless toil and sweat. As such, many had willingly joined the Apostate Cardinal's rebellion and saw fighting for him as a way to escape their miserable lives. A general dislike for the Departmento's then-Master-Prefect on Vraks had also spurred on their support for the rebellion. Many of the labourers had already received some basic military training as the labour corps had also supplied many power for the Vraksian militia. Although only poorly trained, Vraks' militia was a truly massive force. One in four labourers either volunteered or were conscripted into the militia. Lacking any sort of heavy weapons, artillery or vehicles, they were a third line force, but their lack of equipment could be easily rectified and once armed from the stroes, with some additional training, they would be capable enough of joining with the auxilia to hold static defensive positions.

The fourth source of manpower for the Vraksian Traitor Militia were the itinerant pilgrims and the Departmento Munitorum's own workforce of administrators and bureaucrats. These were men with no military experience, but once armed they could hold a defensive position. Whilst many of the pilgrims on Vraks saw the Cardinal as their messiah, most ha no idea who or even why they were fighting. Many volunteered for the Vraksian Frateris Militia raised by the Cardinal in the belief that they would be defending the holy Shrine of Saint Leonis the Blind against heretical forces. They had been told that the enemy were the true heretical renegades and that they must join the Vraksian Militia or see the holy place defiled. These troops were given the lowest priority in weapons and equipment drawn from the Vraksian stores.

To back up these Traitor forces, Xaphan had his own men, former Ecclesiarchy agents and preachers who moved through the ranks traching the Apostate Cardinal's heretical religious gospel and reinforcing the miltia's loyalty. Individuals from the PDf garrison auxilia, many former Imperial Guard sergeants, had been promoted to become the Vraksian Militia's Enforcers. These were the men who would enforce discipline and loyalty much like the Imperial Guard's own Commissars. In combat the Enforcers would stay behind the front lines and shoot any man who fled his post. Added to the Traitors ranks were the dangeously insane and psychopathic, as well as those individuals who had shown signs of developing psychic abilities. Unprotected psykers were always easy prey for Warp entities and there were several hundred such men and women in Vraks Prime's deepest underground dungeons waiting for transportation to Terra on the next Black Ship to arrive. The Cardinal believed these rogue psykers to be his own children, and claimed that they relayed messages to him from the Ruinous Powers.

The forces of the Imperium required to assault these formidable defences would be the Imperial Guard Regiments raised from the world of Krieg, the infamous Death Korps. These were the best Imperial Guard Regiments availble to the Imperium. The men of Krieg were loyal, dutiful and extremely disciplined. They would fight with an almost inhuman disregard for the cost in casulaties, seeing death in battle as the ultimate goal of their lives, to sacrifice themselves for the God-Emperor. The 88th Siege Army would be equipped depending on each regiment's designation. Most of the regiments would be siege regiments, equipped for a long war against static positions, with a special emphasis on artillery. Artillery was the heart of the plan for laying siege to Vraks Prime, and it would be a gunner's war. Large concentrations of heavy artillery would be needed to blast the enemy from their defensive lines, allowing infantry attacks to sweep forwards in their wake. Each regiment would have its own artillery companies, with weaponry ranging from small mortars to the medium artillery of heavy mortars and quad-launchers. There would also be heavy artillery in the form of Medusa siege guns and Earthshaker Cannons, the work-horse of the 88th Siege Army, as well as the heaviest Imperial artillery in use, the deadly Bombards. To augment each regiment's own artillery company, independent artillery regiments would be attached to the army. Other regiments would be equipped as mobile armoured regiments, but for a siege campaign the armoured regiments would be used as breakthrough and gap exploitation forces and would not expect to man the lines as the infantry and artillery regiments would. The tanks would be used to support the infantry's attacks and there would be no mass tank battles since the Imperial forces intended to deny the heretics the chance to engage in armoured warfare. Still, Imperial Guard Leman Russes, Baneblades and Gorgons would all play their part in the siege.

For the men of Krieg, Vraks would prove to be an alien environment. All of them had been raised in the underground hive cities of Krieg, where they became used to the constant overcrowding and recycled air. They ahd trained for battle on their world's blasted surface, amidst the frigid cold and radioactive hot spots of a perpetual nuclear winter and a landscape of ruined buildings and a hideous metallic mass of trench and razor wire all left from the planetary civil war that had devastated the world centuries before. While many of the Death Korps regiments were well-established, they had been brought up to strength with many new recruits who had never seen combat before they set foot on Vraks Prime. Vraks was a barren world, cover in a choking layer of volcanic dust, with little vegetation. Its climate was warmer than that of frigid Krieg, but violent electrical storms were a daily problem, as were the sudden downpours that accompanied them. These storms turned the ground into a churning sea of sticky grey mud as the water drained away into Vraks Prime's dusty surface. The battlefield encompassed the whle of the planet's Van Meersland Wastes, 5,000 square kilomtres of dusty, rocky plains with the occasional outcropping of volcanic rock. The defenders knew his terrain well, but the forces of the Emperor would have to learn the nature of the battlefield as the siege progressed.

The Fortress of Vraks, also called the Citadel, housed the headquarters of the Vraksian Planetary Defence Forces, the Master of the Administratum's offices, the great Basilica of Saint Leonis the Blind, the Cardinal's Palace and the Citadel's own garrison barracks. By the time the Imperial siege of the world began, 3 defensive lines had been constructed to the north, west and south of the Citadel by the rebel forces, with the rest of the area to the south and east defended by gorges and canyons, rendering it unsuitable for a massed attack. At the time of the uprising, work had not been completed on the outer defensive lines, providing the Death Korps' forces a target for the first strike against the heretics' fortress when they arrived on the world in 813.M41.

The Krieg offensive lines were dug in 1000 miles away from the Citadel, making use of Earthshaker and Bombard artillery batteries. A Departmento Munitorum labour corps of 500,000 men was brought in from the Imperial penal colonies of Arphista to lay railway lines across the barren wilderness to support the siege.

The Battle of Fort A-453
On 897814.M41 the grenadiers of the 261st Krieg Regiment of the 30th Line Korps was ordered to conduct a probing attack along its entire front after six months of relative inactivity. The 9th Company of the 261st, under the command of Commander Tyborc, had been given the task of attacking a strong point in the heretics' line, designated Fort A-453. The Death Korps forces were able to move quickly across the no-man’s-land, covered by the smoke from the offensive's heavy preliminary artillery bombardment. Some Krieg troops were able to reach the enemy trench lines under heavy and indiscriminate bombardment. Sending a runner back across the lines to call for reinforcements, Tyborc and his men were able to gain a foothold in the entrance of a personnel shelter, hunkering down as enemy artillery was called in upon them. The runner, having taken several hours to return across no-man’s land, was eventually able to report the breakthrough to the 30th Line Korps' commanding officer, General Durjan, in his own command post. The next day, grenadier units worked their way towards the fort while Tyborc’s men fought a fierce battle in the galleries and corridors beneath it.

The third day of the battle saw the deployment of 3 tank companies from the 61st Krieg Tank Regiment of the 11th Assault Korps, augmented with a Baneblade super-heavy main battle tank. These units were accompanied by Atlas Excavators, equipped with dozer blades to fill in the anti-tank ditch that protected the fort and allow the tanks to cross. Meanwhile, underground, the Vraksian Renegade militia attempted to burn out Commander Tyborc with Flamers. Grenadiers were able to force their way into the underground complex and captured the main access tunnel. From there, corridor by corridor, they were able to clear the complex of the heretics' forces. The men of the 261st ultimately secured the area, narrowly avoiding being attacked by their own men before establishing that they were friendly Imperial forces and members of the 88th Siege Army's 30th Corps.

With more men and tanks thrust into the breakthrough at Fort A-453, the Vraksian Traitors were no longer able to control the entire outer defence line. With the heretics' frenzied attempts to stem the tide, other sectors in the heretics' defensive lines soon became undermanned. The 8th Assault Corps made its way through these breaches and then completely rolled up the heretics' outer defence lines until they were no longer tenable positions. The Apostate Cardinal's units began to abandon their defences and move back to man the second defensive line. Death Riders harried the enemy hard as they fell back en masse. Once the mopping up of several heretical units trapped behind the breakthrough had been completed, the first objective of the Imperial Siege of Vraks had been won.

The Get of Alpharius
By 820.M41, seven standard years had passed since the start of the siege, seven years of bitter and grueling fighting that had seen millions of men on both sides slaughtered for the gain of only a few miles by the Imperial Guard forces as they moved onto the inner defence lines of the Vraksian Citadel. Each side had won victories and suffered defeats, both had suffered terrible losses, but neither side was yet ready to collapse. Lord Commander Zuehlke requested from the Lord Commander Militant of Segmentum Obscurus a new line korps of Imperial Guardsmen from Krieg to join the fighting on Vraks. He believed that these extra men would bring the campaign, already running longer and far more costly than originally planned by the Administratum, back on schedule and help break the stalemate at the Traitors' second defensive line. The order for more men was put through the standard Departmento Munitorum bureaucratic channels and the Adepts set to work to find the needed men from Krieg. The siege took an unexpected turn for the Imperium when a warband of Chaos Space Marines of the Alpha Legion under the command of the Chaos Lord Arkos managed to secretly insinuate his corrupted Astartes among the Chaotic forces defending Vraks in 820.M41. Arkos' Battle Barge, the Anarchy's Heart, had crept into the Vraks System unnoticed and had landed its contingent of Traitor Marines at the Vraks Prime starport, who had passed themselves off as Loyalist Astartes come to join the fight. The Chaos Space Marines had crossed the no-man's land between the Loyalist and Chaotic lines by pretending to launch an attack. Arkos and his followers had presented themselves at the Citadel of Vraks Prime, offering their support in the name of Chaos Undivided for the Apostate Cardinal's cause. Arkos could not only provide the Chaotic defenders with superb superhuman troops, adept at raiding and disruption behind enemy lines, but also better training for the Apostate Cardinal's poor-performing Vraksian Milita units. Arkos could also add his own enormous tactical experience to the defensive campaign while his Astartes, all unflinchingly loyal to their lord and their foul Gods, would relish the chance to join the war. The Alpha Legion had been drawn into the battle by the intensity of the fighting and their own desire to win the favour of the Dark Gods by compounding the slaughter for the servants of the Emperor. Lord Arkos was a useful and powerful ally for Cardinal Xaphan and the Chaos Lord's offer of aid was gratefully accepted by the Vraksian Traitors. The Chaos Space Marines were immediately put to work bolstering the Vraksian defensive lines around the Citadel. This unsettling news was made far worse when the Chaos Sorcerers of the Alpha Legion sent a psychic signal burning through the Warp to call old allies to the support of the Chaotic forces fighting for control of Vraks Prime. Those elements of the Forces of Chaos lurking around the Eye of Terror were drawn like moths to a flame by the flickering psychic light emitted by the Alpha Legion's message that promised battle, slaughter and plunder.

The Angels of Caliban
Observation station DM498-066 was just one of many secret Imperial listening outposts that maintained a silent vigil on the Eye of Terror. Vraks itself had been a collating point for some of this data, with its choir of Astropaths being able to relate any important information obtained by the listening posts to surrounding star systems as an early warning system against Chaotic raids or even an emergent Black Crusade. The station’s sensitive Auspex detected the passage of several large, unidentified vessels in its vicinity, well off the usual trade and patrol routes.

On 054823.M41, the Exuo Squadron of the Imperial Navy on patrol in the Vraks System detected fourteen different energy signatures as the Chaos warfleet called by the Alpha Legion by-passed the system's outer asteroid fields and made best speed for Vraks Prime. Rear Admiral Rasiak led the Imperial Navy's defence of the system from the Lunar-class Cruiser Lord Bellerophon, leading Exuo Squadron's complement of 3 Sword-class Frigates and a hastily-assembled fleet of 3 Defence Monitors, 2 armed freighters, 1 heavy transport and 3 Fire Ships. Despite the reinforcement by the Cruiser Group Marhzur, which arrived not far behind the Traitor warfleet, the Imperial fleet proved unable to prevent several vessels of the Chaos warfleet from entering orbit of Vraks. The Chaotic vessel Aharon’s Bane was badly damaged during the orbital battle but crash-landed on the surface of Vraks, disgorging many of its surviving passengers across the west of the Chaylia Plateau. The Chaotic cruiser Blood Dawn was also able to enter orbit and managed to unleash its cargo of Dreadclaw Drop Pods onto Vraks, which were filled with a horde of savage Khornate Berserkers in the service of a warband of the World Eaters Traitor Legion. The Chaotic warship Ferrum Invictus unleashed a large warband of Iron Warriors Chaos Space Marines known as the Steel Brethren, whose expertise in siege warfare would aid the heretical defenders of Vraks greatly in their attempt to break the Imperial offensive.

Death from Above
With the arrival of the Chaos Space Marines, the situation rapidly deteriorated for the Imperial besiegers. The appearance of Khornate Berserkers stole the initiative from the Imperial Guard of the 88th Siege Army. Khornate warbands, including Traitor Marines from the World Eaters warbands called the Skulltakers and the Berserkers of Skallathrax, roamed the Imperial trench lines, attacking wherever they encountered the enemy. Fort C-585 was attacked by the Skulltakers, who arrived in Drop Pods and then began clearing the trenches of Imperial Guardsmen in savage close combat. The 468th Krieg Regiment was forced to withdraw down Mortuary Ridge. The Chaos Space Marines' sudden arrival forced the Imperial Guard's forces to return to their prior positions, effectively restoring the heretics' outer defensive perimeter and guaranteeing that the siege would continue to grind on.

Confusion Reigns
The arrival of the Chaotic reinforcements radically altered the momentum of the Siege of Vraks. A slow, static war of attrition had suddenly been transformed into a more fluid battle, as the deployment of the Chaos Space Marines provided the Apostate Cardinal's forces with the ability to strike deep behind the Imperial lines. But even the Traitor Marines' warbands lacked the heavy artillery and armoured vehicles required to smash the 88th Siege Army's deeply-entrenched positions, nor were they able to effectively hold onto the ground they had retaken from the servants of the Emperor.

Yet being pushed back on the defensive incurred a troubling cost for the men of the Imperial Guard on Vraks. Cut off from easy resupply efforts because of the Chaotic forces' constant and costly harrying pressure on their lines, the Death Korps' units were no longer able to get the regular resupply of men and materiel that was brought in from off-world by the Departmento Munitorum. Whilst the stockpiles of the 88th Siege Army were vast, these supplies could no longer be readily replenished and the Imperial forces on Vraks were now taking far higher casualties than the Administratum had ever expected when its Adepts had laid out the course of the siege.