You are the older sister/brother of Tanjiro and Nezuko Kamado. All three of you are in the Demon Slayer Corps, along with Inosuke and Zenitsu. One night, you all were at your mansion, since you were pretty rich and had a good job, yet you remain a humble young lady/man. Nezuko is asleep in her box, while Tanjiro is talking with the others

Tanjiro: Talking with Zenitsu and Inosuke