Kimetsu no Yaiba Sibling Scenarios

Switch (Older sister! Shinobu X Younger sister! Demon! Reader

(Reader P.O.V)

I was called into Shinobu nee-chan's office for some experiments with my Blood Demon Art, which is the ability to make any and all living things swap bodies.

She wanted to see how far my power could reach, so here I am, testing it on different animals.

Everything was fine, and calm.

Until a cat got in.

You must be wondering how.

Well, it was summer, which meant it was Hot with a capital H, so Shinobu opened the window, to let some air in.

Hence, the cat.

As soon as the cat got in, Nee-chan started to freak out, trying to shoo it out, so it wouldn't interfere,but since she was anxious, naturally, I felt nervousness building up inside of me, and I made a big mistake.

One moment, nee-chan is shooing the cat out, and the next she's meowing, tilting her head and staring at me while the cat nearly screams out and rushes around the room. And while all of this was happening, I was standing there in the center, terrified. I saw the cat(in nee-chan's body, begin to head towards the open window, which I hurriedly shut, and locked her in a room, so she wouldn't escape.

I turned towards nee-chan (in the cat's body), and bowed vigorously, while apologizing profusely, tears threatened to fall from embarrassment and fear.

I felt something furry brush against my leg, and I opened my eyes to see nee-chan looking up at me, with the same gentle look in her eyes, as she brushed against me.

"(Y/N), it's ok. Just take deep breaths and clear your head. All you need to do, is concentrate, ok, and change me back, ok?", she said, nodding her head slightly.

I sniffled and nodded, before walking with her to where I had locked her actual body in a room, only to see it wide open, no sight of nee-chan's body.

I picked nee-chan up, and ran as fast as I could outside, holding a parasol above my head so I could be out in the sun, and searched under the lilac color of the thin paper, nee-chan helping as well.

I saw Tomioka-san in the distance, walking towards his home, possibly after a patrol, and rushed up to him, tugging on his haori urgently. He spun around with his hand on the hilt of his sword, stiffened, but slowly relaxed when he saw it was just me.

"What is it (Y/N)? You look out of breath.", he said, looking with the same deadpan look on his face.

I explained everything.

When I was done, he was smirking slightly at nee-chan, who was resting in my arms, staring up at him.

"So, big, brave Kocho is this small cat, huh? Hah! No, I haven't seen her body anywhere. Take that Kocho", he said, triumphantly, before turning and walking away after nee-chan hissed at him.

I continued walking, and noticed that the sun was almost setting. I bit my lip in fear, and ran faster, even more desperate than before.

'If I don't switch them back before the sun sets, she'll be stuck like this forever. I can't let that happen. She's my older sister. No way!', I said in my head as I ran.

I was running past the Love Pillar's estate, when she suddenly called out to me. I spun around and saw her nervously fiddling with one of her braids, as she called me over. I rushed over and asked what was wrong, to which she responded this,

"Well, I saw Kocho-san, and invited her in for some sakura mochi, but she started climbing onto the countertops, and the shelves, meowing constantly, knocking things off, so I was wondering what happened. Can you tell me?", she asked, looking straight at me.

I blushed in embarrassment, and explained for the second time that day, what happened. She nodded, and told me she would help.

We both walked inside, me holding nee-chan, while she walked and snuck up on nee-chan's cat possessed body, and caught her, and, while struggling with Shinobu's body fighting against her, asked me to follow her, and we walked into a room, which I assumed was her dojo, and she closed the windows and the back door, before leaving the room, closing the door behind her.

I set nee-chan down, and closed my eyes, concentrating on nee-chan's mind switching back to her body, and the cat's going back to its body. I opened my eyes, and saw nee-chan, back in her body standing, while glaring down at the cat with an angry smile.

The cat's hair stood on end, and quickly rushed towards the door, meowing in fear. I ran forwards and hugged Nee-chan tightly, and she wrapped her arms around me as well, stroking my hair gently.

"Good job,
(Y/N), you controlled your ability, and I believe, that just might be the best experiment yet! I must write this down when we get back.", she said, then started mumbling different ideas, which I giggled at and followed her out of Mitsuri's estate, thanking her as we left, and walked with her under the moonlit sky, my arm around her waist, and her arm around my shoulder.

(A/N: Hey guys I am so sorry I haven't been updating lately. I've been kinda busy, with personal things, and I'm really sorry. But, here's a request from
WellwellwellWelp! Thank you very much for requesting this chapter, and again, I am sorry for the delay.)