Muichiro's childhood is rough, he lost his whole family, causing him to be a lot less expressive. That was, until he joined the Demon Slayer Corp. He quickly became a Hashira with his amazing skills and quickly reaction time.

Time passed he grew attached to you. He saw you as a mother figure since you treated everyone with fairness and coddled him because of his young age.

Muichiro sat patiently by the entrance gates of the Butterfly manor late at night. He never once closed his eyes, as he was waiting for you to return from a mission. He perked up the second the gates creaked open.

"Mama."

He called out in a sweet tone despite his face being stone cold. He sprung up, quickly running over to you and hugging you.