The ragged, bony edge of Mortarion's greatscythe clashed against the adamantium claws of the shadow-beast, the shockwave cleaving the ground between them. Their weapons clashed again and again; the shadow-beast seemingly able to conjure up blades from within itself. Mortarion blocked the beast's incoming talons with the shaft of his scythe, pushing it backwards and following up with a lunging strike. The scythe's blade slashed straight through the shadow, meeting nothing but empty air as the creature disappeared into a flock of ravens. The corvid reformed behind him, and Mortarion turned to block the creature's strike with the hilt of his weapon. It attempted to flank the Daemon Primarch several more times, however each strike was met by a parry of Mortarion's scythe. The Primarch of the Death Guard was too empowered by daemonic energies and skilled with his blade to fall for such simple tricks. The swarm of ravens formed a swirling pillar around Mortarion, filling his vision with fleeting black shapes. Out of this mass the shadow-beast struck without warning, materializing blades-first hurtling towards Mortarion. The Primarch raised his scythe into the air and brought it down upon his attacker with blinding speed. The sound of their weapons clashing resembled the roar of thunder, and the force of their impact drove cracks through the earth and uprooted trees.

The two combatants were pushed backwards, the corvid digging its talons into the earth and Mortarion steadying himself with the hilt of his weapon. Mortarion unsheathed his energy blaster and sent a number of plasma bolts in the corvid's direction, however it merely dissolved into a flock of birds once again. Frustrated, Mortarion yanked one of the numerous phosphex bombs which hung from his armor and lobbed it towards the diffuse swarm. The bomb detonated, releasing a vile cloud of noxious gas which plumed into the air and crawled across the ground. The swarm was sent into a panic, with several of the disparate birds falling dead. The swarm reformed in mid-air, growing its wings to immense size and beating them to create a furious gust of wind. The roaring winds dispelled the phosphex gas, tearing out chunks of earth and stripping the leaves from the trees. Mortarion raised his arms and braced himself to avoid being swept up in the cyclonic winds, before realizing too late that the shadow was already upon him.

The creature's claws dug into Mortarion's abdomen, causing the Primarch to drop his weapon and dragging him along the ground in its flight. The beating of his powerful black wings carried it across the landscape, sending Mortarion's body crashing through trees and rocks. Amidst the sound of snapping wood and crumbling earth Mortarion roared furiously and grabbed the creature's legs. He struggled against the beast, summoning his daemonic strength to break its grip on him. The shadow began rising into the air, and after several minutes the Primarch was able to wrench himself out of the beast's claws. Mortarion plummeted into the earth, crashing and rolling for several meters before digging his hands and feet into the ground and bringing himself to a halt. Mortarion breathed through his respirator heavily, expelling clouds of caustic fumes as he clutched his abdomen. He felt no pain and was largely unimpeded by the injury thanks to his Nurglite blessings, but the damage inflicted upon him by this creature was not something he could take lightly.

What is this thing? Mortarion thought. For it to have such power it must be some kind of Greater Daemon, nay, something even stronger…

Mortarion rose to his feet, unfurling his leathery, worm-eaten wings which left a flurry of toxic spores in their wake.

Now where the hell did my scythe go?

Suddenly he heard a piercing cry from above, and looked up to see the corvid was plummeting towards him in relentless pursuit. He took flight, just barely dodging the hurtling shadow-beast as it shot past him then began circling around to attack again.

"Gods damn it all..." Mortarion muttered, summoning demonic power from his fingertips.

Despite his daemonic ascension gifting him powers that surpassed even the strongest of mortal psykers, Mortarion hated using them. Plagues, chemical weapons, ballistics, blades, all of these he preferred to being forced to utilize the power that he had so hated in his mortal life. For now, he would have to set aside his personal distaste for sorcery to dispatch this wretched creature.

Tendrils of sickly green infestation creeped from his hands, surrounding him like an aura of disease. Thorned and stinging insects spawned forth from the aether, carried upon pestilent winds into swarms that were now Mortarion's weapons. He swung the clouds of insects with a motion of his arms, sweeping them across the forest. The pestilent clouds of diseased flies reduced everything they touched into rot and decay, like the hand of death inflicting an entropic curse. The two opposing swarms converged upon the approaching shadow, wrapping it in an inescapable cloud of miasma and death. Mortarion tightened his psychic grip, further constraining the shadow beast in its caustic prison. Within the dense clouds of rot, he could see the vaporous shadow writhing and churning, struggling against its inevitable dissolution. This was his favorite part, seeing his enemies succumb to the inevitable fate of decay. This one in particular he was going to relish.

Yet that moment would never come. Mortarion felt a burning sensation across his arms and hands, and a pale blue light shone from within the gaseous prison he had concocted.

"What!?" Mortarion shouted.

Jets of ghostly flame erupted in all directions, burning away the blighted tendrils until they could hold their prisoner no longer. Mortarion was blown backwards by an explosion with the force of a small plasma reactor going critical, scorching the earth and leaving behind blackened scars and small embers of blue-white flame. The trees were all burned to ash, purifying the rot inflicted by Mortarion in a baptism of unholy fire. Within the crater left by the explosion the shadow-creature stood wreathed in ghostly flame and burning shadow alike. The creature let out an agonizing shriek and darted towards Mortarion.

The Daemon Primarch took flight, retreating to where he had left his scythe. The shadow burned across the sky in hot pursuit, leaving a trail of blazing darkness in its wake. The two collided in mid-air, sending them spiraling towards the ground. Mortarion balled his fist and struck the beast in the beak several times, eliciting a pained shriek. The corvid slashed Mortarion's neck open, severing his breathing tubes and causing bile and black blood to spill out of his wound. It shoved its hidden blades into Mortarion's chest and abdomen repeatedly, shredding his rotten insides. In response, Mortarion plucked another phosphex grenade from his side and stuck it down the corvid's throat, holding its beak shut with his hands. The grenade exploded in a plume of toxic smoke, and the shadowbeast was forced to relent its attacks by bursting into a flock of ravens. Mortarion crashed through an abandoned ruin on his way down, tumbling through the debris into a large courtyard overgrown with red vines. Mortarion clawed at his ruptured neck and held his torn-open stomach, the sound of his severed windpipe creating a sickly wheezing sound. It wasn't enough to kill him, but it caused him immense pain.

Where does this creature get such strength from? Mortarion thought. No daemon, greater or lesser, has ever given me this much difficulty.

Mortarion rose into the air on his leathery wings, surveying the landscape around him before the creature could reassemble itself and resume its attacks. He spotted his scythe impaled in the earth where he had first encountered the creature and soared down to retrieve it. Suddenly the shadow impaled him from above, sending them both plummeting to the ground. Chunks of earth and stone were sent flying by their impact, and both Mortarion and the shadowbeast tumbled across the ground. Mortarion attempted to struggle to his feet but was immediately beset by the corvid. It thrust forward with its razor-sharp beak, and Mortarion was only just able to stop it before it impaled his skull. With its claws the shadow tore open Mortarion's chest, revealing his beating daemon heart. Its talons shot towards their intended target, but Mortarion grabbed them just in time. The Daemon Primarch and his attacker grappled with one another in a battle of raw strength, a battle that Mortarion was slowly losing. The Primarch could feel his essence slowly draining away from his multiple wounds, even with his unnatural resilience. The shadowbeast snapped its beak at him, while its talons hovered mere inches away from his heart, both held back only by his gradually loosening grip. He feared what would happen should he be banished again, considering the numerous failures he had already endured. He gritted his rotten teeth together and struggled futilely against the raven beast, his decayed muscle fibers twisting and snapping against its supernatural strength.

Then Mortarion began to hear something, a faint noise that rang clear in his worm-eaten eardrums, like no other sound he had ever heard before. It was the sound of hooves trotting upon fresh earth accompanied by the short, powerful breaths of some kind of animal. The more he focused on these noises, the more his other senses were filled with foreign stimuli. He smelled sickeningly fresh vegetation and the scent of a recent rain shower, all things he should have had no knowledge or experience of due to his hellish upbringing. Upon his rotten tongue he tasted something acrid and sweet at the same time, some sort of intoxicating substance he would have never partaken in, unlike some of his brothers. At last, he opened his eyes, and was greeted by the impossible sight of a vast field filled with golden wheat. The shimmering stalks of grain rippled gracefully beneath a deep blue sky, moving in waves across the rolling hills.

"Where… where am I?" Mortarion said. "Am I dead? Is this some kind of punishment?"

You really want to go back to that wretched thing's lair? A soft and boyish voice said from behind him.

Mortarion tried to turn his head to see the source of the voice but found himself unable to move.

"Who are you?" Mortarion said. "What the hell is this?"

I'll help you just this once… but you really must promise to get some fresh air once in a while.

"What the hell are you talking about!?" Mortarion shouted, struggling to move.

I believe I remember how father taught me to do it… no way to know until we try, aye?

Mortarion's eyes shot open, and panic shot through him as he remembered his predicament. This time however, he felt different. His wounds, previously numb and lifeless, were beginning to itch and burn slightly. He felt strange tendrils, almost like roots or vines, moving underneath his skin and stitching his flesh back together. Then an indescribable sensation shot through him, traveling all the way from his feet to the tips of his fingers. Mortarion felt the hand which held back the shadowbeast's snapping jaws start to tingle, as small arcs of electricity were firing up and down the tendons of his wrist. Suddenly a single word shot through Mortarion's mind, a word which he knew neither origin nor meaning of, yet felt it with his entire being when he shouted:

GHROMÓS

A blinding flash of light erupted between them, followed by an earth-shaking clap of thunder. Huge arcs of lightning burst forth, striking down trees and scorching the earth in a savage rain of destruction. The shadow was sent hurtling backwards, covered in tendrils of electricity that crawled all across its skin. The beast writhed and rolled all over the ground, shrieking in agony from the devastating shock. Once it had recovered it leapt to its feet, shaking off the lingering charge that clung to its shadowy form. Mortarion rose and wrenched his scythe from out of the earth. He raised its blade to bear against the wounded shadowbeast, which unsheathed its claws and chittered furiously in response. He stared into its triple red eyes with an expression denoting that they were no longer fighting on unequal footing.

Suddenly the head of a mace struck the shadow's skull, pummeling it into the ground. Before it could recover, Lorgar struck it again with his mace, sending it stumbling backwards.

The shadowbeast shook its head, staggering backwards in a stupor. Its gaze darted between the two Primarchs, staring at them with its unblinking ruby eyes. It outstretched its shadow-dripping wings, screeching in anger and frustration. It beat its wings repeatedly in a display of intimidation, then, as if realizing it was trapped in a hopeless battle, wrapped itself in its shadowy aura and erupted into a plume of ghostly flame and scattering ravens. The birds flew off in all directions, showing no sign of returning as their shrieking calls disappeared into the distance.

Mortarion breathed a sigh of relief, then looked down at his hand. Faint tendrils of electricity shot through his fingers briefly, before disappearing entirely. He balled them into a fist and cast his lingering thoughts aside.

"What in the 4 hells was that thing?" Mortarion said.

"That my dear brother… was Corax." Lorgar said. "Or what's left of him."

"Corvus Corax? That was the Raven-Lord?" Mortarion said. "How is that possible?"

"He must have made a deal with some warp-entity, though I cannot say which. He would not cease his attempts to murder me long enough for me to ask." Lorgar said. "Though I probably would have killed him just the same for all of my men he slaughtered."

Lorgar slung his daemonically-enchanted mace upon his hip. He looked relatively unchanged from when Mortarion had last seen him before his ascension to daemonhood. The most noticeable differences were the grey, stone-like texture of his skin, the burning runes inscribed all across his face, and the crown of horns lining the top of his bald skull. He still maintained the same self-righteous expression upon his face, similar to the one Magnus often bore though less egotistical.

"So, what brings you all the way here to my domain? I don't suppose you came here to aid me in dispatching that pest." Lorgar said.

"I have come in search of information about a daemon." Mortarion said.

"Really? The notoriously stubborn and atheistic Primarch of the Death Guard has come to me for guidance? That's a new one." Lorgar said.

"This daemon crippled my 1st company. Single-handedly." Mortarion grumbled.

Lorgar looked at him with surprise and intrigue.

"That is a powerful daemon indeed." Lorgar said. "Come into my study so we may discuss this further."

Mortarion followed Lorgar into the large black monastery, adorned with runes both colchisian and daemonic in origin. Inside of its halls were countless effigies and fetishes to the many aspects and power of Chaos, the Four being chief among them. These were not, however, the crude etchings and mad constructions of warp-addled cultists from the sewers of some overcrowded hive-world. They were each and every one a work of art, a masterful rendition of the power and terror embodied by Chaos in all its forms. Bronze statues capturing warriors in their moments of death, eternally glistening blood still dripping from their wounds. Howling souls sealed inside of great multi-colored crystals, trapped in time and space yet still somehow conscious of their agony. Terrariums of fungus-infested plants in a perpetual state of decay, crawling with insects feeding upon the corpses of their forebears. Magnificent paintings capturing unearthly delights, the figures within bearing expressions of uncanny pleasure that seemed altogether too life-like.

Lorgar led Mortarion to the entrance of a great tabernacle, a pair of immense obsidian doors upon which was inlaid the 8-pointed star of Chaos undivided in pale gold and flanked by the flaming daemon skulls of the Word Bearer's iconography. Lorgar pushed open the great black doors to reveal a grandiose private study, a mixture of a library and an altar to the Ruinous Powers. It was here that Lorgar dedicated equal attention to the literary study of Chaos as well as to contemplating the deeper mysteries of Chaos by communing with the gods directly.

"Come brother, have a seat." Lorgar said, gesturing to a pair of wooden chairs designed more for utility than comfort. "And tell me more about this daemon."

Lorgar was clearly more interested in this warp-creature Mortarion's sons had encountered than his brother's company. Not that Mortarion was too fond of seeing any of his brothers either, that is. He sighed and sat back into the wooden chair, his leathery wings hanging at his side.

"It seems to have been quite effective against your Death Guard… perhaps a Lord of Change? Tzeentchian Greater Demons have the capability of temporarily nullifying Nurglite enchantments if they are strong enough." Lorgar mused.

"She was not of Tzeentch. Nor Khorne or Slaanesh… or Undivided." Mortarion said.

Lorgar's furrowed his brow.

"But that would mean…" Lorgar said.

"She called herself the 'Daughter of Nurgle'. Had I not seen the effects of her power firsthand I would have discounted her existence entirely. She was able to tear my Deathshrouds apart with her bare claws, not just nullifying but reversing Nurgle's rot. Some of the ones who survived her onslaught have even claimed that she has the ability to remove his blessing entirely." Mortarion said.

Lorgar could only stare at Mortarion with wide eyes in an expression of astonishment.

"What did you say this daemon's name was?" Lorgar asked.

"Tadmushtum." Mortarion said, spitting the word out with malice on his tongue.

"Tadmushtum…" Lorgar whispered.

He rushed over to one of the large unorganized stacks of ancient tomes and pulled one out, opening its leathery cover and thumbing through the off-white pages. He flipped through the book, occasionally pausing to read a few lines with his finger before moving on. When he had reached the end he threw the book aside, rushing over to another stack and repeating the process several more times.

"Not in any of these…" Lorgar muttered. "Perhaps I need to try an older codex."

Lorgar climbed a ladder to reach the top shelf of an ornate bookcase, taking one from the furthest corner. He blew on the cover, kicking up a heavy cloud of dust. When he opened the ancient tome, more dust spilled out of its pages. He slowly and carefully scanned each page meticulously, from beginning to end, before closing the book with a dumbfounded expression.

"That name… it's not any of these…" Lorgar said.

"That is… concerning." Mortarion said.

"No, no brother!" Lorgar said, excitedly rushing over to Mortarion. "Do you know what this means?"

"That I'm still no closer to finding out the identity of the daemon that slaughtered my bodyguards?" Mortarion said in an annoyed tone.

"This is an entirely new and undocumented aspect of the gods Which has never been seen before! At least, not in recorded history." Lorgar said. "A 'daughter' of Nurgle? What kind of being could this be? Would a mere daemon truly be granted such a lofty title? Perhaps it is a new kind of elevated mortal, or something else entirely! Whatever it is, it must be on a level of strength only rivaled by Daemon Primarchs such as ourselves!"

Mortarion's eyes grew dark and serious upon hearing this statement.

"We need to know more about it… we have to find and capture it so that I may document it personally!" Lorgar said. "This could be a revolutionary new weapon in our war upon the False Emperor!"

"I don't care what you do with it, so long as it never attacks my sons ever again." Mortarion said, rising from his seat.

"So, you will aid me in finding it?" Lorgar said.

"If it will please my master… then yes. I do not want to return to him empty-handed again." Mortarion said, shuddering at the thought of displeasing the Plaguefather again after his last failure.

"Excellent! I shall gather my Dark Apostles to investigate this matter further…" Lorgar rambled on.

Unbeknownst to either of the Primarchs, the opened door had allowed another ear to listen in on their conversation. Just outside, perched in the portal of a high window, sat a raven, its head tilting expectantly.

Far away, at the top of a frozen peak situated directly above a humid rainforest, a wounded shadow beat its wings exhaustedly before collapsing into the snow. The aura of shadow slowly sloughed off of its thin frame like layers of mud and dissolved into the air, revealing the gaunt and twisted form of Corvus Corax. His eyes were sunken, and his skin was even more deathly pale than it had been originally, to the point of his veins being visible just beneath. His formerly pitch-black eyes were faded and glassy to the point of almost appearing white surrounded by webs of red veins, and his long, black hair was matted and full knots. His armor had been warped into a thin and skeletal shape, conforming around his body in an unnatural way. The dark transformation he had undergone was taking its toll on his physiology, his skin becoming dark and scaly in some parts and his nails becoming long and talon-like. Small patches of black feathers erupted painfully from his skin, and his teeth were beginning to fall out, replaced by sharp fangs. He was totally and utterly drained.

"Too… exhausted. Can't… continue… not with… both of them…" He uttered.

Corax slumped against a rock, feeling the cold snowflakes landing on his face. He turned his head lazily, looking through drooping eyelids at the raven-haired woman standing next to him. She wore dark leather armor draped with a cloak of black feathers, and her face was obscured by the mask of a raven.

You are weak. Too weak to fight. You must consume more daemon hearts and grow stronger. The raven-masked woman said.

"Each heart… gives me less energy… than the last." Corax said between labored breaths. "I have to consume more each time… I can't keep doing this for much longer."

It was not we who set you upon this path of vengeance. A brown-haired woman said, wearing the mask of an owl.

She wore heavy robes of furs and wool beneath a cloak of eagle feathers and spoke with a more aged voice than the raven-masked woman.

"It was you who said that I must kill Lorgar." Corax said.

I said that Lorgar would be killed as a consequence of his betrayal. The owl-masked woman said. You decided to become the instrument of that fate on your own. We merely gave you the power to do so.

If it is fated to be, why must you torture yourself with this sacrificial crusade? A third woman said with a soft and innocent voice.

The last woman had silver hair and bore the mask of a dove. She wore a loose and elegant dress of white silk and was draped in a cloak of swan feathers.

"I cannot depend on fate to carry out justice." Corax said. "Lorgar must die."

The daemon they spoke of, Tadmushtum... The raven-woman said. She sounds exceptionally powerful. Not only that, but she had the power to nullify Nurgle's power. If you could take her heart and consume it… it could give you the power to overcome Mortarion and Lorgar combined.

Corax dug his feet into the snow, steadying himself with hand on the rock behind him. He struggled to his feet on shaky legs, pushing his pain deeper inside of him to focus on his mission.

"Very well then." Corax said. "I will take this Tadmushtum's heart… and then I will tear out the hearts of Mortarion and Lorgar. I will enact vengeance… on behalf of my father."

Shadows began to grow around his feet, coalescing into a pillar of darkness that consumed the sickly Primarch. The shadows coated his skin and armor like a parasite, digging into and eating away at his soul. His form twisted and mutated into the red-eyed raptor-like beast that had haunted this world for millennia and let out one final shriek that struck fear into every Word Bearer upon Sicarus. Then, as quiet as the wind, the phantom disappeared into a flurry of black feathers.