You and him were childhood friends. Your were very close. Due to a turn of events you were separated. You became a demon slayer and after some time you became a hashira. It was during a meeting. Master Ubayashiki was introducing you to the hashiras. You for complety forgot about Muichiro and how he looked

Muichiro was staring at you the whole meeting, you looked familiar but he couldn't quiet remember from where, he wanted to remember.

"Do I know you?" He asked you after the meeting