In the first age, in the first battle, when the shadows first lengthened... one stood.

"W-What?"

Medea stepped back in shock as she saw her arm flung across the pavilion, command seals flashing red and disappearing. Whatever she thought would come with this ritual, her summoning had produced something even the ancient witch could have never imagined

"Another world to plunder?"

A red maw, gaping in a screaming agony and lined with ethereal teeth, opened wide on the ground where her summoning circle had been. Someone emerged from it, a sickening old man of metal and malice, crowned in bronze and wearing a smirk that promised suffering. His eyes were filled with fire, a blaze that threatened to consume her very soul.

"W-What are you?" she asked.

"A servant of a higher power."

An orb of red light coalesced in his palm and she knew no more.

He chose the path of perpetual torment.

Kirei stopped in his tracks.

"Something is here," he spoke to his companion.

"Oho?" Gilgamesh cocked an eyebrow. "Pray tell."

He opened his mouth to reply, but the burning in his hand stopped him. He threw his holy book to the side as it caught on fire, and its flames licked at the wooden floor in hunger. The podium, the rafters, the chandelier, all soon followed and caught alight. The stained glass window shattered, imploded, and Kirei jumped back to avoid the rain of debris.

A roar, a thunder of a thousand eons, pounded in his ears, and a large muscular arm erupted from his chest. Blood spat out from his lips and agony flared around the wound, and he was thrown carelessly to the wall. The beast was an ocean of flesh, wielding two cannons that glowed a sickening yellow.

"You dare?!" Gilgamesh shouted as he donned his armor with a golden flash, his gates appearing in quick succession. The beast was made quick work of, its scream neither human nor animal in nature. But the king could not rest on his laurels, for he found himself on the end of another pair of cannons, much bigger and painted in flames.

Kirei's vision began to darken as he saw the golden dust drift alongside the ashes.

In his ravenous hatred, he found no peace.

Rin was atop a skyscraper with Archer when the rain began.

It announced itself with the loudest crack of thunder she had ever heard in her life, something that made her shriek and cringe away. The clouded sky flashed and began to bleed. The clouds, sobbing in crimson, twisted and whirled until they screeched and tore a hole in the sky.

"Rin!"

A strong arm pulled her back, and Archer was in front of her instantaneously as, in a painful flash of light, something appeared in front of him. Its limbs extruded out from its joints and its face was twisted into a sadistic rage. It was designed to be feared.

Two blades of light and darkness formed in Archer's hands, mirrored falchions that sliced through the limbs of the creature until it gave a dying scream and crumbled into ash. But the Servant of the Bow had no time to breathe, as the scream of his Master and the sound of a gem shattering spun him around. Another creature was shimmering with a purple veil, an outstretched claw languidly falling down to slash at her.

As soon as Archer decapitated it, the two of them were surrounded by a flood of shambling corpses and hideous demons. Rin was already at his back.

"Archer! We need to—"

He scooped her into a bridal carry and jumped, tracing and breaking a phantasm to obliterate the mob behind them as they fell away. Landing was of no concern to him. The situation was.

"What the hell is going on?!" his Master shouted. "What kind of Servant could have done this?!"

They couldn't have. This would be more like a Dead Apostle Ancestor or...

"No," he said. "It's a Beast. It has to be."

And with boiling blood, he scoured the Umbral Plains...

Sakura realized that something was wrong as soon as the Servant failed to appear. She could feel the growing disappointment and frustration in the glare of her grandfather (the thing that should not be) as the project he had invested so much time and energy into failed him. The glow of the summoning circle began to fade, and his sigh gave her a momentary fleeting hope that maybe, just maybe, she wouldn't have to—

Blood that wasn't hers erupted from her mouth, the taste of sulfur and ice left on her tongue and she spat it out. She hunched over and vomited, dark crimson bile suffocating her as she tried to get rid of the foreign liquid.

No, that's my blood, that's my blood, it's supposed to be mine it isn't foreign

She couldn't stop, though. Her body was in rebellion against itself. Her vision pulsed in shades of red and gold, and in the corner of her eye she could see her grandfather staring, unblinking.

"Hmm..." he said as she spat once more. "A Pseudo-Servant, perhaps? Something more incompatible with you than it thought?"

A tear in reality opened behind him, a dark red portal that bathed the room in a glower of hatred. A gray muscular arm carrying a longsword emerged and impaled him, the blade drawing a straight line from his skull through his spine. Before he could let go of his mortal form, black fire encased him, and all of the worms that he was trying to dissolve into screamed as they were obliterated.

She could feel the crest worm inside of her die, and as her vision began to pulse even quicker, knew that she would soon follow.

The arm fell down as its bearer emerged; a barely humanoid thing, misshapen and unbalanced in form with large horns crowning its head. Armor clanked as it walked toward her, red eyes aglow without feeling.

It kneeled before her.

"Maykr..." Its baritone rumble could have shaken the earth were it not so distorted by electronics. "What would you have us do?"

She stood up. No, it wasn't her, she wasn't the one who was controlling her muscles, the one who was moving her lips—

"Establish a collection facility," said a voice that wasn't hers, "and begin processing."

...seeking vengeance against the dark lords who had wronged him.

Shirou's home, his refuge, was not safe.

He knew this even as he shoved his gate open and hastily tried to lock it behind him. It was pointless, of course. As he sprinted away, the demon had already phased through, its spiked jaw cackling as it trailed after him.

The reinforced pipe he had been fixing had already proved itself useless against the purple beast, but still he gripped it tightly as he turned around, trying to figure out how he could get himself out of this mess. It was all he had, but it failed him again as the creature phased behind him and punted him across his yard into his shed.

"Agh!"

His ribs cracked on the cement floor. It took all he could to even move aside to prevent another blow through his gut. The demon chortled, its toothy jaw flapping in amusement at his struggle. It wanted him to fight just so it could make him suffer further.

Shirou stared into its triad of glowing red eyes, empty of soul and empty of thought. He had watched it tear people's limbs off and let them try to flee, only to pounce upon them as they came so close to escaping. He had watched as it expressed sheer joy from the carnage it had created, a sadistic ecstasy that only the most vile beings could relish. The only way he was able to save anyone was by drawing its attention and running.

The last time he had died, it was on his back, having killed off everything that made him human and accepting that it was his time to go.

This time, he refused to go down without a fight.

He took his pipe in hand once more, clutching it in both hands. He had nothing to say to something like this. All he could do was scream and face his death head on.

Shouting defiance, Shirou threw himself forward. The demon's arm swung forward with a heavy inevitability to punch through his chest—but before his sternum was shattered, a bright blue light flooded the room.

And those who tasted the bite of his sword named him...

Shirou had already fallen to the ground, clutching his eyes and covering his ears. The echo of the blast was still ringing when he faintly heard a gurgle and squelch of flesh being torn apart. After a few moments he managed to open his eyes, squinting through the black spots in his vision.

The demon had been torn in two, and the pieces of its carcass were strewn across the floor. Standing above them was a tall man, clad in green armor and carrying what looked like an entire armory's worth of weapons. The soldier turned toward him, his face barely visible through the visor, and extended a hand to him.

"T-Thank you," Shirou stuttered as he was pulled up. He could see the soldier's gaze, heavy and firm, as he took him in. The man said nothing, but held out the firearm gripped in his armored gloves. Shirou couldn't even recognize what it was, and stood frozen for a few moments until the man grew frustrated and roughly shoved the gun into his chest.

"W-what?"

He received no verbal response; instead, the soldier threw a small carton at him. He was aware enough to grab it out of the air. His eyes widened as he opened it and found it full of shotgun shells.

What... did he just give me a shotgun?

Shirou quickly looked up as furious howls tore through his yard. The soldier pulled out an even larger firearm, thick, gray, and blocky. Before Shirou even realized that more demons were streaming into his yard, the soldier was dispatching them with ease. Their bodies were shredded by a rain of lead, and when they lunged forward, a long blade extended from his arm to tear into them.

The blood and entrails that decorated his grass made him sick, but he barely managed to hold it back. As the last demon fell to one final bullet to the head, the soldier looked back at him, his rifle held lazily at his side. Behind him, Shirou could see plumes of smoke billowing from all across the city. No longer fearing for his life, he raised his head to the clouded sky, the crimson drizzle, and the screams. The echoing screams of dying people begging for their lives the smoke the fire the numbness encroaching on his soul

The flashback faded as the gun in his hands was ripped from his grip. The soldier had taken it in one hand, and with a single smooth vertical motion, loudly cocked it. He flicked his head backwards.

"Your city is facing imminent destruction." A voice projected out from the suit of armor, but he couldn't see the soldier's mouth move, and the tone did not match him at all. "The Slayer is tethered to your world through the seals on your hand and already has a plan to neutralize the demonic threat. He is offering you the chance to fight and to save your people."

He spoke before he even had a chance to think.

"Yes."

The man nodded and threw the shotgun at him. This time, Shirou caught it.

"The nearby park has a newly grown Gore Nest," the electronic voice said. "My models are indicating that eliminating it will prevent losses upwards of 47% in the neighborhood."

The unfamiliar fire of hatred flickered in his chest, and instinctively he tried to quench it. But at the heart of the flame was the memory of Ayako being torn to pieces. He clenched his jaw. He didn't need any other justification. There was no mercy, no saving these things. They needed to die.

The soldier strode out of the property. Shirou's grip on the gun tightened and he hurried after the man—no. This soldier was more than a man. No name could capture what he was. Yet Shirou could feel his identity engraved into his bones, see his title in the sunlike aura that shone off his armor. The Hellwalker, the Unchained Predator, The Feared One...

The Doom Slayer.

Happy April Fool—oh shit.

This was meant to be an April Fool's chapter for The Saga of Shirou's Summons, but time passed and things got in the way and now it is a May Fool's chapter instead! I may continue this at some point. This only happened because I played a lot of DOOM Eternal. Beat it on Nightmare-No-HUD, so much fun.

Thanks to my Loresingers for their help. In particular I appreciate KentaKazami for providing the original suggestion.

Your ending theme is, of course, At Doom's Gate by Mick Gordon.

Thanks for reading.