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Demon? I'm just trying to buy milk!

Summary:

Izuku's attempt to purchase milk somehow takes him hundreds of years in the past in the gruesome world of Demon Slayer. As a hero, he of course takes it upon himself to save as many lives as he can! If only people would stop calling him a demon...

Chapter Text

Izuku woke up with a splitting headache, a rough hand grabbing him by the shoulder. He squinted. Above him stood a burly man, muttering something incomprehensible as he stared him down. The boy scratched at his hair as he tried to discern words - the thick dialect making it no easier for him in his daze. A question, for him; he’d gotten that much. “M’sorry sir, could you repeat that…?”

The stranger squinted at him warily, “I said, what are you doing here?”

Izuku groaned before sluggishly arranging himself into an upright position. His hand jostled something plastic, and he looked down to see a brightly-coloured bag. The sight of milk cartons splayed about on the ground jogged his memory. He was just walking back to the 1-A dorms after a brief grocery run. Of course, he’d just wanted to buy some milk of all things before he woke up to a stranger yelling at him, and feeling like someone had smashed his head in.

As his mind slowly cleared, he looked at his surroundings, slightly irritated at his inability to blink blurry spots out of his vision. A full moon framed by wispy clouds shone brightly in the dark sky, illuminating what looked to be some sort of remote village. A rough stone path lay beneath his fingers, extending into the distance. The path was flanked by rows of wood-columned traditional houses.

The stranger cleared his throat impatiently, and Izuku’s attention snapped upwards. He found around him not just one person; but a small group of wary faces, pointing towards him and whispering amongst each other as more people joined them from the streets. The strangers looked rather intimidating in the flickering flames; all of them adorned in traditional Kimono, as the boy remarked; though quite a bit plainer than the one he’d seen Todoroki wear during the Gion festival. Then and again, his family definitely was on the wealthier side of things… 

“Honestly, I’d really like to know that just as much as you do. Some kind of quirk if I had to guess?” Izuku answered earnestly. How in the world could he have possibly managed to get this lost on the way to the corner store? He knew that he had gathered himself a bit of a reputation as a trouble magnet but… “How far exactly am I from Musutafu?”

“Musutafu?” The man looked at him a bit oddly, pausing a moment as he looked away, searching for someone in the crowd. “Kimura-sama, have you heard of such a place?” An ancient-looking man in the back shook his head, silently. “You seem to have taken quite a hit, kid… If the elder doesn’t know of anything by the name.”

“No, I’m sure I got it right. I’m a student at UA high school, after all,” Even if the man somehow had never heard of Musutafu before, surely he’d heard of UA, right? 

The confused looks he received from the group only concerned him even more. He may have been sent even further than he originally thought.

“Where am I right now?” Izuku asked, stifling the rising panic in his chest.

“You might not have heard of us, this place is pretty tucked away after all. Nanika Village on the western end of Shizuoka Prefecture.” The first man replied gruffly. “We heard a loud noise, and came to investigate. We thought you were dead at first kid. You nearly gave me a heart attack.” 

“Shizuoka? But Musustafu is the largest city and one of the most popular-” Then and again, the parts of Shizuoka he knew didn’t have anyone running around dressed like that, either, outside of holidays. Or talk in a dialect that he could barely comprehend… Some remote, alternative community he hadn’t heard of, perhaps?

His thoughts were quickly interrupted by the sounds of a door banging open, jarring bright light flooding the darkened street. 

A teary-eyed woman ran out from the doorway. “Have any of you seen Haru?!” Izuku winced sympathetically at the distress in her voice.

The villagers immediately rushed over to her, leaving only a few near him. As odd as this place looked… He was still a hero, and likely the only one around. As his instincts kicked in, Izuku quickly sprung upwards, albeit a bit unsteadily. He had really hit his head hard, hadn’t he? A potential concussion didn’t matter at the moment though, and he rushed over to the terrified woman, just in time to hear a panicked explanation.

“I was watching over him the entire night, I swear! An-and I looked away for a moment, but when I looked back, he was gone! And the window was open!” The woman choked out. “Please, please help me!”

“Did you see anyone?” A villager knelt down next to the woman with an arm on her back, trying to calm her.

“No, no! Not a single sound! He was there one moment, and then he was gone!” She answered quickly.

The man’s eyes widened, shaking visibly as he spoke. “I’ve heard of this happening throughout the prefecture, but I never thought much of it… Rumours, I’m sure they’ve reached your ears as well!” he whispered nervously, the villagers around him growing quiet as he spoke. “They live on humans, drink our blood… Disappearing without a trace, they materialize in one moment and are gone the next. It… would match up.”

At that, the villagers paled, looks of terror resting upon their faces. Izuku looked at them confusedly. Perhaps, the people here still had their superstitions, far away from civilization… Still! A child had disappeared.

“I-I’m sure Haru will be fine! I’ll find him, I promise,” The boy said resolutely. “I’m a Hero after all!”

Heads turned back to him; skeptical, though Izuku internally smiled at the hopeful glimmer in the woman’s eyes. “ Hero? ” 

“Yeah, it’ll be alright!” He put on what he hoped to be a comforting smile. “Could you tell me where you last saw him, Miss?”

“You don’t really look all that fit to play the hero, kid.” A young man in a dark kimono gave him a look of disdain.

That was probably due in part to his uncontrollably short stature, and the baby fat that still clung to his cheeks, despite the harsh training regime all hero students were required to partake in. The fact that he was likely concussed and faintly wobbling evidently didn’t help his case either… Izuku did his best to stand tall, answering the question with a nod. Very carefully, the woman lifted her finger, pointing towards the back of the house. 

“Trust me sir, I’m a hero student at UA. I’ve been trained for situations such as-” The boy’s eyes grew wide as a muffled cry erupted from the building, followed by a sickening thud.

In a flash, Izuku sprung onto his feet, rushing into the doorway, and towards the direction he had heard the noise. The interior of the house was just as old-fashioned as the outside; screen panels lining the halls, and the texture of the bamboo floor mats ground on his heels. He looked around frantically, seeing nothing out of the ordinary, the silence in the room deafening. A shiver traveled down his spine. Warily, he crept around the room, eyes on every faint glint of the light, or shadow that seemed to move ever so slightly. 

If it hadn’t been for his experience fighting villains much deadlier and quicker than himself, he would’ve missed the slight pressure against his ear. Instinctively, Izuku ducked, feeling air pass over him before something crashed behind him with a loud thud. The boy jumped back, eyeing the large hole that had appeared on the wall, right where he had stood a second earlier. 

His eyes darted sideways, as an inky figure emerged from the shadows. The mutant quirked figure was tall, with blood-shot eyes, greyish skin, and two large horns protruding from their forehead. Tattoo-like markings lined the figure’s skin, disappearing beneath a loosely worn kimono. Izuku’s heart stopped as his eyes trailed downwards. Gnarly, clawed fingers were enclosed around a young boy’s arms. Freshly bleeding marks had been left on the boy’s arms, as though he had been harshly dragged. The look of horror on the child’s face was enough to make Izuku gag, and hold in a wave of nausea.

But no, now wasn’t the time. Izuku shook himself out of the daze. A monstrous grin had stretched against the villain’s face, eyes squinting in morbid delight - before the figure disappeared in thin air once more with the child in hand. Invisibility quirk, well at least I have some practice there from Hagakure… But what about the mutant characteristics? With those horns and - 

The boy’s thoughts were interrupted as he dodged a strike from above with a step to the side, before quickly turning around with a punch. The villain gave off a frustrated screech, but seemed otherwise unfazed. Before it had the chance to disappear once more, Izuku charged toward the thing - feigning another punch before jumping into the air. Shoot style - 10%.

The kick landed on the villain's shoulder, sending the child in his arm tumbling down… along with the arm. Izuku looked at the torn-off limb in horror, twitching on the floor still grasping at the boy. He hadn’t put that much power into that, had he? And his punch earlier barely seemed to hurt the thing at all!

To his utter shock, however, the bloody nub on the villain’s shoulder bulged before exploding outwards, as a new arm quickly formed in its place. Nomu! Or at least something close to it…

The villain growled, “mind your own business, won’t you! The prey is mine.”

Prey? It sure was a strange way to refer to your victim, but Izuku had heard of weirder things before. He powered up One For All, prepared to dart forwards and bring the child to safety-

“Huh, that’s strange, I didn’t expect to find two of you here.” A saccharine voice drew Izuku’s attention. At the window stood a young woman, in an elegant white and pink Haori; almost reminding him of a butterfly. A long, thin sword hung loosely from her waist. 

“Fighting amongst yourselves, how sad… But I suppose I shouldn’t blame you for your nature, hmm?” The woman smiled dangerously.

Seemingly caught by panic, the invisibility quirk villain made a dash for the door, grabbing the boy. Before Izuku could react; the stranger’s blade sliced across the man’s neck. The villain convulsed for a few moments, before his body clattered onto the wooden floor, unmoving. 

“Y-you killed him!” Izuku slowly registered, quivering at the sight of the dead, empty eyes that stared back at him.

“Yes. That’s part of my job. I couldn’t let him escape with that poor child.” The woman said, in a seemingly regretful tone, pushing the (still breathing, thankfully; as Izuku noted) body of the boy in question aside. “I wasn’t told that there would be another demon, however.” She pondered, “The instructions they give us are rarely ever reliable though. Well, it just means a bit more trouble for me.”

“This is your Job? ” Izuku gritted his teeth. No one takes killing a person that lightly! “Who do you think you are?”

“Oh! I forgot to introduce myself! How very rude of me. Demon Slayer Corps, Insect Hashira. Kocho Shinobu. And who would you be?” The stranger asked, inquisitively. 

“Well, I’m a hero, and it’s a hero’s job to fight villains such as you!”

“And here I thought we could be friends. It’s pretty funny though, a demon that thinks of itself as a hero?” The newly-deemed Shinobu chuckled.

“Demon?” Izuku asked a bit uncertainly, eyes remaining focused on the threat in front of him.

Shinobu seemed to come to a realization, “Oh! Are you newly turned? Poor thing. And at such a young age as well…” the woman said, a frown forming on her face. “I’ll make this quick then, yes?”

The Hashira lifted her sword, poised for a strike. Yet when she brought it down, nothing but empty air hit the blade. “You’re a quick one, aren’t you!” She stated, no concern showing in her voice as Izuku narrowly dodged a flurry of strikes, each faster than the previous. 

He could barely get a hit in, too focused on dodging the deadly attacks; the tip of the blade barely nicked Izuku’s cheek, spilling warm blood over his skin. All of a sudden, she stopped her attacks. “Ah, you’ve been hit! The poison of my blade will kill you demon-kun, can you feel it? The wisteria is lethal for your kind…” She smiled, sympathetically.” Stand still so I can make it quicker for you.” 

Like THAT was gonna happen. Izuku took a step back. When he had first entered the building, he had noticed a window on the side that faced a thick forest. Charging up One For All, he jumped through the window before rolling onto his feet in the yard behind the house. He threaded between houses and greenery as fast as could, not looking back to check whether the crazy villain woman was catching up to him. He continued to dart through overgrown brush as he neared the forest, only allowing himself to catch a breath once he was deep within the woodland. His eyes darted around in paranoia, but he found nothing looking back at him but trees. Relieved, the hero allowed himself to relax.

As he braced himself against a tree, his haggard breaths slowed. He began to feel… rather hazy, a fog coming through his head. His vision blurred and spun; he grasped at the bark behind him for support before everything went to black.

 


 

Back in the village, Kocho Shinobu gazed off in the direction of the forest as she brought the child back to his family. It had been in her intentions to finish it off then and there, but she had more important matters to attend to than chasing a demon that was doomed to die regardless. It couldn’t have run off far, the concentrated dose of poison that she had given it had rarely ever failed her. Even if something had felt just a bit off about this one…

As the teary-eyed mother came running towards her, the Insect Hashira turned away, once more adorning a gentle smile.