Muichiro and you were siblings, you grew up together until your parents died. After being attacked by a demon when you were still quite young, you two got separated, and Muichiro forgot about you since he became amnesic become of the trauma. After a few years, he became a hashira, but you became a demon. While he was on a mission, hunting down demons, you two met again, but, he had no memories of you. He got ready to attack you if you dared moving an inch.