He was calmly meditating in one of the rooms, sitting cross-legged on the floor. Tanjiro had annoyed the shit out of him earlier, so it was good for him to have some time to himself. That is, until he hears someone entering the room.

As you enter the room, he looks up at you. You're whining, a red handprint on your cheek. You walk up to him, pouting. "Muichiro, Sanemi hit me!" You whined. He has always been like a brother to you. He sighed, rubbing your back. "Oh, you poor thing."