chained : yan ! bnha + kny x kny ! reader

one , portals

Y/n sighed, it was like any other day for the Sin's Hashira. Another demon was attacking a town that they could care less about.

Unlike the other, more selfless, demon slayers, Y/n did it because they were bored. They had no big tragic backstory about their loved ones being attacked by demons, they were simply bored one day and decided to become a slayer.

After training under Rengoku, the Flame Hashira, they took the exam and passed as easy as that. Apparently, his training was gruesome, but Y/n didn't know any better. It seemed mediocre to them, perhaps even easy, in a way.

That was for one simple reason, Y/n wasn't fully human. Sure, they weren't a demon either, instead they were in a limbo. They were able to be out in the sun for much longer than any demon could, but they would eventually have to seek shelter. However, they could also regenerate limbs; albeit slower than any demon could.

Though Y/n wasn't sure of all of the details, they knew it was because of a woman named Tamayo. She had been trying to create synthetic demons, and Y/n volunteered to help.

It was a failure, as they learned soon after, but it was inches away from success. They weren't a full demon, more like half of one. Half as strong, yet also half as weak.

This, of course, caused Y/n some problems. They lived much longer than any human, and aged much slower. It seemed that, despite being years older than it, Y/n was physically 16.

They did still age, however, as they were only physically 6 when they had first been turned, and it had been twelve years since then.

Being half demon had its upsides, but many downsides as well. One of them being the fact that the progenitor of all demons was after them.

At first, it was little off handed comments demons would throw at Y/n. They'd mention not to hurt them too bad, or that their master would be pleased with them.

Then, it got stranger, demons would stalk Y/n late at night, yet they would never harm them. It got to the point they could feel a lower moon's presence trailing them.

But lately, it's gotten even worse, upper moons would come across Y/n too often for it to be a coincidence, though they would never fight, only talk.

Y/n would report it to their master, but could come up with no solution. Y/n simply had to endure it until the moment was right. Endure it until they could strike.

At some times, they found the upper moons enjoyable, and found themself missing the company. This was one of those unbearably lonely times.

Y/n had been walking for ages, but couldn't find the demon they were looking for.

It wasn't some wild goose chase either, just some boring search for a nobody demon.

Y/n's footsteps clacked against the ground, coming to a halt when they started to feel an unwelcome presence. It was a demon, they knew it. The Sin Hashira quickly ran towards the feeling, stopping once it became almost too strong to handle.

The demon in front of them had long black hair covering most of her body, all besides her scrawny legs and wrinkly hands. It was a sight to see.

Most would have assumed the woman weak, but Y/n could feel her aura. She was strong, and intoxicating. Maybe even stronger than the twelve kizuki.

Y/n gripped onto their dark red sword, eyes narrowing at the demon intensely. The demon walked foreword, almost limping, "It's you, the half-demon slayer," She mused, her hands clawing at her own face.

The woman's hand reached out to claw at Y/n's chest, only for them to dodge swiftly.

The slayer's hold on their sword tightened as they remained stedfast, "If you want to bring me to your master, you'll need to try harder than that!" They boasted.

The demon laughed, "And what if I'm not bringing you to my lord?"

"Even better," They said in a husk voice before launching themself into the air.

The demon's claws raised into the sky and pointed at Y/n. A sort of black mist shot from her hand and Y/n dodged it effortlessly.

"Sin breathing, form one:" They spoke under their breath, "Wrath!" Their sword infused itself with fire as then launched themself at the demon woman.

The demon's hands secreted a circle of black mist around her, making Y/n jump back. They grit their teeth, the woman was too on guard, they needed a distraction.

"Form three: greed!" They shouted, attempting to create an illusion of desire for the demon, but nothing appeared. Y/n faltered, leaving the demon an opening for them to attack. They shot the mist at Y/n, who cut it as it launched. However, the sword did nothing to the mist, only fazing through it.

Y/n then dodged it, however it swooped over and made a B-line for the slayer. Y/n glanced to the demon itself, running up to it in an attempt to cut of it's head.

The demon put up a barricade of the mist last second, and Y/n couldn't stop. They slowed down, but it was no use. They were being sucked into the mist, and if they left now the trail already following them would take them instead.

Y/n smirked, "See you in hell," They said before falling through the portal while cutting the demon's head off.

The next thing Y/n new, they were falling from the sky of an unknown place. Y/n calmed down, trying to figure out how to not break all of the bones in their body, when an idea came.

They gripped onto their sword, "Sin breathing, second form: gluttony" They spoke, and suddenly their movements were slower, and more controlled. They used total concentration breathing to control more of the fall as well, and prevent more injuries. They were now falling at only half the pace they were before, and landed smoothly.

When they landed, they saw buildings taller than any they'd seen before, and vehicles unknown. They weren't simple automobiles, they were far more advanced than the cars Y/n knew. They were amazed, they could take in that sight for ages.

Though, the moment was ruined when a grey scarf took hold of their limbs.

Taisho Era Secrets
-> Rengoku doesn't like it when you go on missions without him...
-> That demon was stronger than some of the upper moons...
-> Muzan knows what happened...