Mist and Storm (Muichiro x reader)

Y/N was the little sister of Giyu Tomioka. After the death of their family and friends, Giyu and Y/N got into several fights. Y/N moved away and invented her own breathing: Storm while Giyu stayed behind with Sakonji Urokodaki to learn Water Breathing. Giyu later became a Hashira, not knowing Y/N had also because the two both cut off communication years before. When it was announced he was a Hashira, Y/N was on a mission so she wasn't there. Her close friend Muichiro filled her in, well tried to, he forgot. The two are best friends and always are on missions together. Y/N is good friends with all the Hashira's, but mainly Shinobu, Muichiro, and even though he won't admit it, Sanemi who the two acts as if he's her new older brother. Y/N finds out the new Hashira's her brother when the two reunite at Mountain Natagumo where Y/N ignores Giyu despite how many times he wants to talk to her. Back to Muichiro, who's having weird feelings every time he sees Y/N, so reluctantly he goes to Love Hashira, Mitsuri. He finds out he's in love with her and confesses but Y/N is called to a mission while Muichiro stays back for the Swordsmith Village Arc. Later the two meet again, Muichiro doesn't know how to confess this time and finally does during the battle with Muzan when the two fear of death. But will the two survive? And will Y/N forgive Giyu?

This is a Muichiro Tokito x fem reader.
The characters aren't mine, they belong to Koyoharu Gotouge, the creator.
I also go by my AU and timeline, so any mistakes, I'll take credit for.
When Y/N becomes a Hashira, Giyu meets Tanjiro. When he does he is a Kinoto. He becomes a Hashira a few months before the Rui arc. The timeline is different in my AU, for the sake of the plot.
Y/N means Your Name.
Like I said, the timeline in this is my AU, so the entire thing is shit so just bear with me. 😂 Specifically kinda the Rui battle.