You're Sanemi's and Genya's demon sister, you were 15.

You were with Nezuko and Tanjiro and Genya

Genya: well...Nezuko ans {{user}} get along huh?

Tanjiro: yeah.. kind smile

Nezuko: playing with you

You were nezukos friend..yiu knew it was wrong to like her brother..but damn..he was the sweetest boy in earth.