"Heliotrope" KNY Oneshots

Big Brother | Muichiro x Fem!Reader (Fluff)

Requested by alicew14

Sibling relationship

(f/f): favorite flavor

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The stares of the Hashira were overwhelming. Even though they weren't the usual piercing glares they gave all newly prompted Hashira, the young girl standing before them was still intimidated to have the nine most powerful demon slayers staring down at her. "Now no need to be frightened (Y/n)." Kagaya said in his usual soothing voice.

(Y/n) felt the heavy weight on her shoulders lift. She smiled and cleared her throat. "Hello I'm (Y/n) (L/n). You can just call me (Y/n)."

Mitsuri was the first to welcome the young demon slayer into the Hashira group before asking the golden question on everyone's mind. "How old are you (Y/n)-chan?"

"8." 

"Woah! So, then you're younger than Muichiro!" Mitsuri pointed to the short boy who had been staring up at the sky in a daze the whole time. "Muichiro, looks like you'll be a big brother!"

Muichiro glanced at (Y/n) for no more than a minute before staring back at the sky. The rest of the Hashira meeting was spent talking, mainly getting to know (Y/n) more. Afterwards, as the Hashira made their way out of the garden, (Y/n) approached Muichiro.

"Muichiro, do you want to get some mochi or something?!" (Y/n) asked, naturally drawn to him because of their ages. Muichiro didn't answer her question right away, making her think that he wasn't uninterested.

"Okay." He finally answered which made her smile happily.

---

Muichiro and (Y/n) were seated on a bench not too far from the mochi stand, eating (f/f) mochi. (Y/n) blushed with each bite she took of her mochi. "Delicious."

Muichiro ate his mochi while still in his dazed state of mind. It broke for a moment as he thought of how the flame Hashira, Kyojuro, would loudly state that his food was delicious much like (Y/n) right now.

"Awe such cute little kids." An old woman cooed as she passed by the two kids. "Like boyfriend and girlfriend already."

(Y/n) choked on her mochi at the woman's comment. "He's not my brother! He's more like my big brother!"

"And she's not my girlfriend you hag." Muichiro said crudely, making the old woman gasp and scream about Muichiro's rudeness as she walked away.

(Y/n) held back a laugh then diverted the topic. "So Muichiro how did you become a demon slayer so early on."

Muichiro was silent for a moment. He hadn't told anyone about his past or at least what he knew of it as most of it was a blur to him. He figured it wouldn't hurt to tell (Y/n) what he knew so far. "Amane-sama found me in my home near dead from a demon attack. That's all I know."

"Oh my. I'm sorry." (Y/n) hugged him though he didn't seem bothered recalling it.

"What about your past?"

"Same thing actually. My parents died to a demon attack. I survived because they hid me in the basement and Himejima-san found me."

"I see." Muichiro mumbled, looking out at the sunset. "I suppose we should get going. Demons will be coming out soon."

"Yeah." The two finished their mochi and headed out of town.

---

The sun rose on the next day bringing the long night to an end. Muichiro and (Y/n) had been sent on joint mission after joint mission the whole night and came out unscathed due to their individual prowess combined.

"Morning at last." (Y/n) said, leaning up against Muichiro as she fought sleepiness. Muichiro's tiredness was hidden by his stoic expression.

"Let's go to my estate. It's closer. I'll have the guest room set up for you to sleep." He said and (Y/n) nodded at his offer. She took a wobbly step forward and nearly passed out, but Muichiro caught her and opted to carry her on his back.

"Thanks, big brother." (Y/n) mumbled half asleep. Muichiro stood still for a moment, feeling a sense of nostalgia at the mention of 'big brother'. He figured that he used to say it in his forgotten past.

I'm the big brother now. I'll take care of (Y/n). He thought as he began walking home. "Your welcome, little sister."