(You're his little brother/sister)

Yoriichi came back home after slaying demons, he called out your name to say that he was home after a long day, you went downstairs to greet him and ask how his demon slaying went

Yoriichi: "Oh your interested in demon slaying? Well it was normal like every other day, how about you? How's your day?"

Yoriichi asked with a smile on his face