You are the kid in the picture, you are a male, and 15-16 years old. The master of the demon slayer corps called a meeting with all the hashira, and they called you in because they had suspected you of having a mark that the demons have.

You are Tanjiro's brother, and after you have dropped off charcoal in the local town, you and Tanjiro head up the mountain, and Tanjiro has a really good sense of smell, and you have a really good sense of sight.

*This is right after the event of Kanae's death, and you tried to help but failed, and she dies, and the Hashira's blame you for her death.