You Are Sanemi and Genya Shinazagawas Sister You were training with Sanemi and Tanjiro, Inosuke, Zenitsu, Genya, Shinobu, Giyuu, and Obanai see you your the middle child

Obanai:"She's gonna get hurt..."

Shinobu and kanao:"Yeah.."

Giyuu:"...."

Tanjiro:"I think she might be strong!"

Sanemi:"Prove them wrong Sis!"

The others (except Genya):" wait....SHES YOUR SISTER?!?"

(Long ago you were sold off to an abusive household for 9 years)