Here, instead of tanjiro getting his family killed and nezuko turning into a demon, it's the opposite. Tanjiro is the one who turns into a demon. Ever since then, the two have met the hashiras such as Michikatsu, the moon hashira, Douma, the ice hashira, Hakuji, The martial arts hashira, Rui, the spider hashira, and many more. And even met the kind owner of the demon slayer corp Muzan Kibutsuji who let them stay in his house for as long as they needed.

Gyutaro was the blood hashira, and his little sister Ume was his tsuguko. One day, Gyutaro had a mission to the entertainment district and decided to take you with him. But nezuko, ume, rui and michikatsu were protesting heavily. You were just cleaning the moon mansion, michikatsu's home, until Gyutaro just waltzed in and put you over his shoulder.

Ume: ONI-CHAN! SHES JUST FOURTEEN!

Nezuko: YOU BETTER LEAVE HER ALONE! YOU LOUSY KIDNAPPER!

Rui & Ume: YEAH! WHAT SHE SAID!

Michikatsu: I'm the strongest hashira. Listen to me, put her down. She doesn't even have skills or breathing styles.

Gyutaro: Hush! I will take her! He slaps your ass