Note: The following is a fan-created work. Warhammer 40,000 belongs to Games Workshop, which deserves credit for making the most badass universe in fiction.
I. Praise the Four
Private Mrita Konvalos sat down, exhausted, atop a pile of heretic corpses. Rain hissed on the still-hot barrel of her lasgun.
"Now is not the time to rest, Konvalos!" her sergeant shouted. "On your feet!"
Mrita thought she had earned a break—of the couple dozen heretics lying dead in this trench, she'd killed eight—but there was no arguing with the NCO. She stood, and checked the power pack on her weapon. "Where to now, ma'am?"
"The hill by Samson's Crossing." The sergeant, Merce Hetz, marched ahead, and the whole of Third Squad trudged through the muck after her. Six of them remained, in tattered and filthy Cadian-pattern armor, their bayonets dripping blood. "They've got a couple of Hydras up there, keep shooting down our air support. But our platoon needs to regroup first."
The battlefield was a morass crisscrossed by trenches, where war simmered but did not blaze. Little moved around them—just a few knots of wary Pirean troopers like her, prodding the dead with bayonets, and, further out, rumblings and small firefights where the enemy still resisted. As promised, black-painted and spike-adorned Hydras spat flak atop a hill in the distance. Judging by the shell blasts launching brown-grey plumes around them—Pirean regiments were known for their artillery—those positions probably wouldn't survive long enough for Third Squad to make any difference.
So Mrita marched forward, slowly but warily.
"How many more of these you think we'll have to clear out?" asked a soldier beside her. Her name was Enthilde, another private, stocky and black-haired where Mrita was a thin redhead.
"Couldn't tell you."
These trenches had been a bastion of heresy on this world, their denizens now put to rout in the Emperor's name. To secure that victory, the Eighth Pireans had struggled for a week and died en masse, only prevailing in the last few days' frenzy of violence.
"Think His angels will show up and save us the trouble?"
"Maybe, but there are only so many Astartes—wait a minute." Mrita held up her hand. She'd noticed a deep shell crater beside the trench, perfect for an ambush. "Cover me, I'm going to check that out." She climbed over the rim and angled the barrel of her lasgun against any heretics who might lie in wait.
There was only half of one, it turned out. The damage looked to her like a chainsword cut—ragged but much neater than dismemberment by shell—and had probably been inflicted by the regimental commissar, Vant, who'd spent the battle charging into the thick of things, seemingly immune to bullets. Entrails were scattered everywhere and stank like sin.
The heretic was unnaturally pale, all of them were, and he had the eight-pointed star carved into his forehead. A similar star was cast in brass and affixed crudely behind his head like a perverse halo.
"Ugly bastard, huh?" Enthilde said, coming up to look over Mrita's shoulder.
"Extra dedicated, too. Look at these parchments." Mrita bent low, tugged at a few bloodsoaked scraps of paper hanging from the heretic's robes. The rain was already washing out rows of disorganized, sloppy text that could not possibly have been Low Gothic. "Might've been a witch before our commissar cut him in half."
Fear the witch, the priests back home had always said, and suffer it not to live. In the Emperor's galaxy, the worshipers of false gods got what they deserved.
Even though it was unclear exactly what they worshiped.
"What are you two looking at?" called Sergeant Hetz. "We have a schedule to keep, guardsmen!"
Mrita turned from the body. "Just checking our surroundings, ma'am. The Emperor rewards vigilance."
"He also rewards punctuality, so—"
A torturously high-pitched screech came from… somewhere. Mrita and Enthilde covered their ears, as did the sergeant and her other soldiers, as did the muddy figures of Second Squad fifty paces away.
"What in the Emperor's name?" Hetz shouted, nearly inaudible.
Mrita winced as the sound grew louder, a shriek of agony clawing at her senses. Buried beneath it was a whole chorus of voices speaking gibberish. For moments the torment continued, until the scream cut out and the voices diminished to a mere whisper that made her hair stand on end.
"Lieutenant Gorivan, Commissar Vant, did any of you hear that?" Hetz tapped the comm-bead in her ear. "Shit. I can't raise anyone."
Mrita glanced over at Second Squad, only to find that they had vanished. Beyond a few meters' distance there was not a living soul on the battlefield. She blinked, disbelieving, scanning the ruined terrain for any sign of her allies…
Even the nearby Chimeras had stopped in their tracks.
"Emperor protect us," said Enthilde, behind her. "He should be dead."
"What?" Mrita turned and saw for herself. In the mud at the bottom of the shell crater, the heretic witch had begun to stir, pulling himself up with his thin, tattooed arms.
"Chaos comes," he whispered. "Sorcery and decay, ecstasy and wrath—glorious screaming madness, like you pathetic souls have never seen."
Something squelched not far away. Down in the trench was another cultist back from the dead, standing upright even though her chest was a burnt and bloody hole.
"Praise the Four..." the heretic said. Corporal Maukan decapitated her with a lasbolt, and she still stood.
"Death to the False Emperor!" shouted a body half-buried under a crushed Munitorum crate.
"You fools serve a corpse!"
There were others, Mrita didn't know how many, mutilated cadavers springing to life from the trenches and the corpse-piles and the endless fields of muck. By her feet, a severed arm pulled its way towards her.
The witch was doing this. Somehow. Mrita jumped into the crater and stabbed him with her bayonet, repeatedly, as if he were another sack of flour on the training field. He cackled even as the blade pierced his lungs.
"Do whatever you like!" he said, spitting blood. "Your efforts only feed the true gods!"
Mrita thrust the bayonet through the back of his mouth, which shut him up. He gurgled and clawed at her rifle with long, grimy fingernails.
"Praise the Four!" the dead went on. They were everywhere now, in the trench and the wasteland around it, seemingly immune to the cracking lasbolts Enthilde and the others put out.
"Death to the Corpse Emperor!"
The impaled witch still thrashed about, his bare fingernails scratching furrows in the side of Mrita's lasgun. That shouldn't have been possible.
"Praise the Four!"
A dozen voices spoke, inside Mrita's head: Praise the Four.
She shrieked. Her muscles spasmed, no longer under her control, and half-seen visions assailed her, specters of blood and fiendish desire and crystal cities where the sky was a riotous maelstrom of colors…
The witch stopped moving. Mrita returned to reality. She withdrew her bayonet, panting, then stabbed him again, and again. When she looked up she saw that the heretics had all collapsed back into the mud.
"Third Squad," Hetz said. For a moment she gazed absently past Mrita, then refocused. "Third Squad, I need a headcount. Have we lost anyone?"
Mrita crouched in the blood-spattered shell crater, Enthilde sat dazed at its rim, Maukan, Hetz, Guthro, and Aelim were knee-deep in mud down in the trench. They had everybody.
"No casualties, ma'am," Maukan reported, though that was overstating it.
Around them, clusters of other soldiers pressed forward on the mopping-up operation, seemingly undisturbed, and Mrita could not for the life of her tell where they'd gone.
"Warp-sorcery," Enthilde said. She put her rifle in the crook of her arm and made the sign of the Aquila.
"Foulest sorcery," Hetz replied. "The Emperor protects."
This was the Warp, yes. Mrita had heard it. Something vast and powerful had bled into this world, twisting reality to suit its whims, hiding an army and resurrecting the dead to chant blasphemous praises.
She remembered another name. The Ruinous Powers, a former squadmate had called it, during the Tyranid invasions back home. To her knowledge the man had later been dismissed, maybe shot. But, he had known and feared what he'd spoken of, as had many of the soldiers huddling around the fire on that bleak, overcast night.
The Ruinous Powers.