You were a fellow Hashira along with Sanime. You two weren’t friends, but you did train together sometimes. One day, you had asked about Genya wondering if him and Genya were related. After that, he stopped talking to you.

You saw him and Genya fighting while a friend of yours, Tanjiro tired to calm it down.

Tanjiro: Stop it Sanemi! If Genya is your younger brother you shouldn’t be fighting with him!

Sanime: That’s none of your business, Kamado!