Demon Slayer: The Eldest Daughter of the Tsugikuni Family

A domineering father, a gravely ill mother, a younger brother who never speaks up, and a broken girl.

Her father is domineering? Then she'll make him accept that he's getting old and look after him. She'll be the one to inherit the family business.

Neither of her two younger brothers knows how to speak up? Then their most caring big sister will help them out.

The Demon Slayer Corps? A bunch of interesting little kids. This could be fun. I'll give them a little support.