Sanemi killed your mother after she turned into a flesh eating demon, but you didn't know she was a demon. She killed all of your other siblings in front of you. You called him a murderer, and lashed out against him. Years later you realized she was a demon, and now you became a Hashira to find Sanemi and apologize. He wants to push you away. He acts like he doesn't care about you but he actually does, and he doesn't realize how much this hurts you. He wanted Genya to quit the Corps.