Slayers in a Demon's World {Demon Slayer x The Promised Neverland}

Prologue

An unrecognisable tune of humming could be heard from the insignificant temple up the hill. The path was wet from the nearby waterfall and the recent rainfall as a girl wearing a f/c haori with cherry blossom prints ascended the stone steps. She sighed, shifting her hand under her haori to unsheathe her weapon - a light magenta Nichirin blade.

What would she do with it? The normal people didn't know.

Only a certain group knew of the katana's use.

"Now," she swiftly brought the weapon out of its case and continued approaching the temple, hearing a creature within the walls. "I'm pretty sure this is the temple Oyakata-sama's crow told me to tend to."

In the dim lighting of the scenery, the girl's shadow was noticed by a nearby family who were cleaning up after the downpour.

"Mama, who's that?" a small girl in a dark green kimono approached an older lady who was holding a broom and a bucket.

"I have no idea, Suzuki," she huffed and gathered the bucket full of wet leaves. "We shouldn't bother them. Come on, Sakamoto and Suzuki. We've got to prepare dinner."

"Alright!"

The girl reached the top of the hill, emotionlessly entering the temple like a marionette. "Ara-ara~ the scent of blood here is so strong!"

"Who are you to enter my territory!" the demon turned around, exposing its fangs over a dead, human body. The sight was enough to freeze a normal human to the ground, but demon slayers like her had seen much worse than this.

"I'm Y/n L/n, Kinoe rank in the Demon Slayer corps," Y/n brought her blade up to her fingers, examining the blade. "It seems that my blade is a bit blunt from slicing off so many demon heads. Forty-eight at this rate since I rose to Kinoe, and you'll be my forty-nineth before I'll be assigned as a Hashira. Maybe you'll be the last one before I get this polished again!"

"I'm not so easy to defeat, kid," the demon hissed, unsheathing its claws and pouncing on the girl.

"Sakura Breathing: Seventh Form: Falling Blossom Blade," Y/n murmured, watching her blade create a satisfying slice which quickly disconnected the demon's head from its neck. "Sayonara. You lost."

"H-How!" the demon spluttered, looking up at the girl into her e/c eyes as she held his head.

"I'm not a Kinoe for nothing. Now, sayonara," Y/n bitterly concluded, dropping the head and stabbing it with her katana for extra precautions.

"Mama..." Suzuki whispered before she entered the house. "There's a lot of noise up there. Can I go up and make sure the girl is okay?"

"Sure. Take a lantern with you," the lady lit a candle and placed it in a lantern before handing it to the kid, watching her race up the path.

Someone's coming. Y/n thought, bringing out a bag from the back of her boot and gingerly placing the body inside before tossing it into the forest surrounding the temple. I'll have to get another one after this.

Hastily, Y/n kneeled on the ground and pretended she was praying when a girl in a green kimono opened the door.

"Oh! Sorry to disturb you, miss," she exclaimed, her face heating up in embarrassment. Suzuki noticed the scene was perfectly clean as if nothing happened. Earlier, her parents asked her to clean up the temple so surely the sounds didn't mean anything.

Y/n turned around, fake smiling to the girl. "Oh, it's fine. I was just about to finish up here."

"I heard some noises," Suzuki explained, fidgeting while Y/n hid her sheathed katana under her haori. "Are you okay?"

"What noises?" Y/n raised her eyebrows as she turned to the girl. "I'm done here and during all the time, I heard nothing."

"O-oh, then I must've been hearing things! Sorry, ma'am!" Suzuki apologised, bowing her head down before turning around.

"Just call me Y/n L/n, though the last name isn't needed, so just call me Y/n-san."