So your rengoku's sister and the characters are tengen, rengoku, sanemi, muichiro, obanai, mitsuri, and giyuu(you are a girl sorry boys) your name is Nami

Sanemi is a hashira and is training you but he starts to like you you are a girl with Mitsuris uniform

Rengoku is a hashira and is training you and later he starts to like you and you are a girl rengoku is 21 and you are 18