Shadow Crusade

. The Shadow Crusade was a joint campaign conducted during the opening days of the Horus Heresy into the rest of the Realm of Ultramar by both Primarchs Lorgar Aurelian of the Word Bearers Legion and Angron of the World Eaters Legion. The two Traitor Legions proceeded to lay waste to the Ultramarines Legion's realm, rapidly destroying twenty-six worlds in quick succession. This campaign ensured the success of the sorcerous Ruinstorm, which would ultimately divide the galaxy in two, effectively cutting Ultramar off from the rest of the Imperium. Ultimately, the campaign was successful, but it resulted in the death of the entire population of Angron's homeworld of Nuceria, setting the World Eaters Legion onto the path of damnation, as well as the apotheosis of Angron into a Daemon Prince of the Chaos Blood God, Khorne

History
During the opening days of the Horus Heresy, Lorgar had ordered his two most trusted advisors, First Chaplain Erebus and the Dark Apostle Kor Phaeron, to unleash their wrath against the Realm of Ultramar. This was done in retaliation for the humilation the XVII Legion had been forced to endure by being forced to kneel in disgrace before the Emperor and Roboute Guilliman and his Ultramarines on the world of Khur by the XIII Legion at the Emperor's orders during the Great Crusade. The Word Bearers proceeded to achieve a monumental victory at the Battle of Calth which ensued. The Ultramarines Legion was badly crippled and no longer presented a viable threat to Horus' plan to drive on Terra. Erebus had managed to complete his blasphemous ritual on Calth's surface, which summoned the beginnings of the sorcerous Ruinstorm to the galaxy's Eastern Fringe -- a monstrous Warp Storm larger and more destructive than anything space-faring humanity had witnessed since the days of the Age of Strife.

Simultaneously, with the Word Bearers' assault on Calth, Lorgar and the more reliable Word Bearers under his command launched a second offensive, a joint Shadow Crusade with his brother Angron's World Eaters Legion into the rest of the Realm of Ultramar, laying waste to the Five Hundred Worlds with reckless abandon, slaughtering twenty-six worlds in rapid succession. This was to ensure the success of the sorcerous Ruinstorm, which would ultimately split the void asunder, dividing the galaxy in two and rendering vast tracts of the Imperium impassable for centuries, effectively cutting Ultramar off from the rest of the Imperium. This prodigious Warp Storm would deny needed reinforcements to the Loyalists as Horus drove on Terra in an attempt to overthrow the Emperor of Mankind. Nothing from Terra would get in and nothing would get out. Not even an astropathic whisper would be able to pierce this storm of Warp energy bleeding into realspace.

During this campaign of destruction, Lorgar had come to realise that over the course of their Shadow Crusade, Angron's temperament and mental stability had steadily grown worse. His cybernetic neural-implants known as the Butcher's Nails were killing him faster than Lorgar had originally imagined, faster than anyone realised. The rate of degeneration had accelerated very quickly in the months after the Battle of Calth. The implants had never been designed for the peculiar genetics of a Primarch's brain. Angron's physiology was trying to heal the damage produced by the implants as the Nails bit deeper. To save his life, Lorgar convinced the Lord of the World Eaters to go back to his homeworld of Nuceria. The overlords of the gladiatorial games on that world who had first hammered the foul device into Angron's skull would know more of the implant's function than the Traitor Legion's savants and the Dark Mechanicum. The two Primarchs would learn all that was known about the Nucerians' insidious cortical implant technology, and then they would burn that loathsome world until its surface was nothing but glass. Angron would finally take the vengeance he pretended to no longer desire. Whether Angron fought him, hated him or trusted him, mattered little to Lorgar, who intended to drag Angron into the immortality that he deserved before the Dark Gods whether he wanted it or not.

The Purge of Nuceria
Guilliman's retribution fleet, which had been tracking the rest of the Word Bearers Legion in the wake of the Battle of Calth, finally caught up to the Traitors upon Angron's homeworld of Nuceria, which the World Eaters Legion were preoccupied with wiping clean of all life in vengeance for the treatment the Nucerians had merited out a century before to Angron. The XIII Legion warship Courage Above All, Guilliman's temporary flagship, broke Warp at the system’s edge, at the head of a large void armada consisting of 41 vessels. The Ultramarines armada looked wounded, cobbled together from separate fleets. It was not a dedicated interdiction war-fleet, but clearly a ragtag strike force, a lance thrust to the enemy’s heart. Guilliman himself had done the best he could with limited resources. The XIII Legion's Cruisers and Battleships ran abeam of the enemy fleet for repeated exchange of broadsides, offering targets too big and powerful to ignore, while the rest of the Ultramarines fleet used calculated Lance strikes from safer range. The armada then divided its assault potential, doing its utmost to destroy Lorgar's flagship Fidelitas Lex, and attempted to take the World Eaters' flagship Conqueror in a boarding action.

But the Ultramarines' warships not only fought a void war, they also attempted to take the fight to the surface of Nuceria, for this attack was personal. The Ultramarines had come for revenge against Lorgar and the Word Bearers, just as they had pursued Kor Phaeron all the way to the Maelstrom on the other side of Ultramar. Several Ultramarines warships attempted to make a run on Nuceria, haemorrhaging Drop Pods, landers and gunships, forcing planetfall by any means necessary. The Ultramarines fleet swept over and against the Traitors like an insect horde. But the tenacious commander of the Conqueror, Lotara Sarrin, put up a difficult fight and destroyed a number of Ultramarines vessels that attempted to make a run for the surface. Though the World Eaters' flagship transformed a number of the smaller vessels into flaming wreckage, the Ultramarines eventually punched through her tenacious defence and managed to land troops on the surface of Nuceria.

Meanwhile, the Fidelitas Lex was already a ruin, its armour pitted and cracked, its shields a memory. The cathedrals and spinal fortresses barnacling along its back were gone, laid waste by the Ultramarines’ incendiary rage. The XIII Legion's armada attacked in strafing runs and protracted exchanges of broadsides, trading fire with the superior warship and accepting their own casualties as the cost of bleeding the bigger vessel dry. Each assault left the Lex weaker, firing fewer turrets and cannons, taking punishment on its increasingly fragile armour. But she fought on. Crawling with smaller ships, the Lex lashed back with its remaining Macro-cannons, rolling in the light of its own burning hull. Guilliman guided the battle from the command deck of Courage Above All, and had decided that the Lex would die first, killed in the death of a thousand cuts and swept from the game board, while the Conqueror would be boarded and killed from within. In the course of the battle in Nucerian orbit, the Conqueror could not rise to its sister-ship’s defence. Both Traitor Legion flagships fought alone, starved of support and suffering the endless attacks of the XIII Legion’s ragged armada. Salvation Pods streamed from the Lex’s sides and underbelly, along with heavier Mechanicum craft and bulk landers. With the Legionaries of the Word Bearers already on the surface, the ship’s human population fled in the vessel’s final minutes. And still the great vessel fought -- rolling, turning, raging. The Ultramarines Cruisers that drifted past burned as badly as the warship they were killing. This void battle was a form of dirty fighting between warships, too close for the neat calculations of ranged battery fire. Instead, it was an up close and personal slugfest.

The Ultramarines Battle Barge Armsman intercepted the Conqueror and came abeam, launching Assault Carriers and Boarding Torpedoes. While the World Eaters flagship was busy repelling boarders, a number of smaller XIII Legion vessels slipped past her defences and launched Drop Pods, gunships and troop carriers. The first Drop Pods hammered home on the planet's surface. Sealed doors unlocked and the first Ultramarines poured forth, Bolters raised, moving in perfect and well-trained unity. But the World Eaters were waiting for them. Those not lost to the Butcher's Nails at once had the presence of mind to note that these Ultramarines weren not the pristine cobalt-blue warriors they had previously faced on the War World of Armatura. These Legionaries of the XIII wore cracked Power Armour, still scarred and burnwashed from some horrendous battle weeks or months before. These were hardened veterans of the Calth Atrocity. They burned with a cold intensity to carry out the vengeance in their hearts, and were intent on getting to grips with the Word Bearers.

As was their way, the Ultramarines established footholds at defensible positions, clearing room for their reinforcements to land. For every position they held, another was overrun by the World Eaters in a storm of roaring axes, or lost to the Word Bearers' chanting, implacable advance. The XII Legion crashed against the XIII in rabid packs, showing why Imperial forces had feared to fight alongside them for decades. Uncontrolled, unbound, unrestrained, they butchered their way through Ultramarines strongpoints, enslaved to the joy of battle because of the Butcher's Nails cortical implants sandwiched within the meat of their minds. The XVII Legion also met their Loyalist cousins, replacing ferocity with spite and hate. The Ultramarines returned it in kind, hungry for vengeance against the vile Traitors who had defiled Calth and damaged its star. Word Bearers units marched, droning black hymns and chanting sermons from the Book of Lorgar, bearing corpse-strewn icons of befouled metal and bleached bones above their regiments.

As the fighting raged, the burning shell of the Fidelitas Lex cut through the clouds into the planet's atmosphere, shuddering on its way east, rolling ever downwards, achingly slow for something of such scale. The weight of the Lex's massive plasma engines dragged the stern down first, colliding with the Nucerian ocean's surface far from shore. In the meantime, the demigod in gold and blue had finally found the object of his obsession amidst the clamour of war. Guilliman confronted Lorgar, possessing the advantage of two weapons, but Lorgar's Crozius gave him a reach his brother lacked. When they first met, there was no furious trading of frantic blows, nor were there any melodramatic speeches of vengeance avowed. The two Primarchs came together once, Power Fist against War Maul, and backed away from the resulting flare of repelling energy fields. Their warriors killed each other around them both, and neither Primarch spared their sons a glance. Lorgar flicked the clinging lightning from the head of his Crozius, shaking his head in slow denial.

Both Primarchs fought without heeding their warriors, their godlike movements an inconceivable blur to the Space Marines fighting around them. None had ever imagined the heroes of this new age would take the field against each other, nor could they have predicted the wellsprings of spite between them. Guilliman confronted Lorgar for what his Legion had done across the Five Hundred Worlds of Ultramar. In his righteous anger the Ultramarines Primarch struck Lorgar with one of his fists, battering the Word Bearers Primarch's sternum. Lorgar repulsed him with a projected burst of telekinesis, weak and wavering, but enough to send his brother staggering. The Crozius followed, its power field trailing lightning as Lorgar hammered it into the side of Guilliman’s head with the force of a cannonball. Both Primarchs faced each other beneath the grey sky, one bleeding internally, the other with half of his face lost to blood sheeting from a fractured skull.

As the two Primarchs were locked in their furious life-and-death struggle, they were oblivious to the destruction being wrought around them. Suddenly, Angron burst forth from the Ultramarines ranks, his armour a shattered wreck, and both of his Chainswords spat gobbets of ceramite armour plating and scarlet gore. Angron was plastered with the blood of the slain after hours in the crush of the front lines of intense combat. On his chest hung a bandolier of skulls taken from the mass grave at Desh’elika Ridge. Blood painted them as surely as it marked Angron. Even through the constant pain generated by the Butcher's Nails, that pleased him. He wanted his deceased brothers and sisters to taste blood once more. He had carried them with him across Nuceria, letting their empty eyes witness the razing of his former, hated homeworld. The World Eater launched himself at Guilliman with murderous hatred. The two Primarchs fell into a seamless, roaring duel where Lorgar and Guilliman had abandoned theirs. Guilliman found himself forced back by the storm of Angron's blows.

Once on Nuceria, Angron had paid his respects to his fallen brothers and sisters amongst the Nucerian gladiators he had once fought beside, whose bones now lay exposed to the elements on the Desh'elika Ridge where they had died. The painful memories of that day, long ago, were too much for the Primarch to bare. After paying a visit to the city-state of Desh'ea to see who ruled the Nucerian city-state that had once claimed to own him, he became enraged when he was told the tale of how he had fled at the Battle of Desh'elika Ridge, and the subsequent massacre of the rebel army in the mountains. The rebels had died to a man in his absence. Enraged by the lies that had been told about him over the last century, Angron ordered his Legion to kill everyone in the city. Then they were to kill everyone on the planet. At the height of the final battle against the last city on Nuceria, Lorgar was confronted by his wrathful brother Roboute Guilliman, who had been chasing him and the XII Legion since the destruction of Calth. As the two Primarchs fought, Guilliman gravely wounded Lorgar and was about to deliver a killing stroke to his wretched brother. But Angron had seen Guilliman's assault upon Lorgar and intervened, facing the Lord of Ultramar in single combat.

On Angron's chest hung a bandolier of skulls taken from the mass grave at Desh’elika Ridge. Blood painted them as surely as it marked Angron. Even through the haze of pain created by the Butcher's Nails, that pleased him. He wanted his former brothers and sisters, the Eaters of Cities, to taste blood once more. He had carried them with him across Nuceria, letting their empty eyes witness the razing of the high-rider cities. As the two Primarchs fought, Guilliman landed a glancing blow, his fist pounding across Angron's breastplate. One of the skulls of Angron's fallen kinsman that hung from the chain worn across his breastplate was partially shattered and scattered across the ground. As the two fought, Guilliman landed a glancing blow, his fist pounding across Angron's breastplate. One of the skulls of Angron's fallen kinsman that hung from the chain worn across his breastplate was partially shattered and scattered across the ground. Guilliman stepped back, his boot crushing a skull's remnants to powder. Angron saw it, and threw himself at his brother, his howl of wrath defying mortal origins, impossibly ripe in its anguish.

Lorgar saw it, too. The moment Guilliman's boot broke the skull, he felt the Warp boil behind the veil. The Bearer of the Word started chanting in a language never before spoken by any living being, his words in faultless harmony with Angron's cry of torment. Lorgar enacted his dark plan to save his brother's life, summoning the Ruinstorm to the world of Nuceria, tearing the sky open and unleashing a crimson torrent, formed from the ghosts of a hundred murdered worlds, raining blood. Lorgar focused his concentration on the triumphant form of his mutilated brother, calling for the Neverborn, the entities men called daemons, to answer in kind. He locked Angron’s muscles, setting fire to the synapses in his brain. The first spasms wracked their way through Angron’s sinews, turning his blood to quicksilver, then to lava and at last to holy fire. His cries of thwarted rage were tainted by an agony beyond comprehension. His body started tearing itself apart, growing, rising. Perfecting, after a lifetime of broken torture. This was the moment of Angron's apotheosis into daemonhood.

The World Eaters Librarians, those few who had never received the deadly Butcher's Nails implants which were inimical to psykers, sensed the fey powers summoned by Lorgar from the Warp. In an attempt to halt the Urizen's dark plans, the 19 remaining Librarians harnessed their collective psychic powers to manifest a psychic entity known as the Communion, the gestalt consciousness of 19 psychic minds. In the midst of Lorgar's incantations, the Communion pulled the soul of the Primarch from his body. The two psychic entities confronted one another within the Warp, locked in a deadly contest of wills, each convinced that they were the one responsible for saving Angron. But ultimately, the Communion failed, for Lorgar was just as powerful in the Warp as he was in the material universe. After Angron's completed metamorphosis into a new Daemon Prince, the Daemon Primarch turned his attention to the Librarians. The creatures that had pained him for decades. The warriors that had made the Butcher's Nails sing and his brain bleed just for the sin of standing near them. Now they moved against his brother, hurling their foulness at Lorgar, who crouched one-handed and wounded, down on his knees.

The Daemon Primarch's rage killed the remaining Libarians, each of them tasting a different doom. Angron killed the last of the Librarian, expunging his Legion of the weakness that had plagued his gene-sons since his reunification with them a century earlier. The Librarius of the World Eaters, the last fragment of the War Hounds within the XII Legion, was no more, a fact which greatly pleased the Blood God Khorne, who would not brook the existence of any psykers amongst his chosen servants. Lorgar had offered up the XII Legion to the whims of the Blood God as his loyal servants. Now there would only be blood, an ocean of blood carried on a tide of eternal slaughter.

The gravely wounded Guilliman escaped from Nuceria, unable to face or even fully comprehend what both of his brothers had become through their corruption by the Ruinous Powers. The World Eaters completed their purge of Nuceria until not one human life remained on the benighted world. Angron, now the very embodiment of the Blood God's Eight-Fold Path, shook the dust of the world from his feet and did not think of it again. Lorgar believed that he had "saved" his brother. In his mind it was the only way, for he alone had sought to save Angron from the implants that were killing him by degrees. Only Lorgar had found a way to free Angron from an existence of unrivalled agony, and he alone had acted to save his tormented brother. Now the Shadow Crusade could move on from Ultramar and rejoin Horus. The next target for the Traitors would be Terra itself.