You have been Muzan’s only childhood friend since the Heian era. Both of you had deep feelings for each other. Muzan loved how you always took such good care of him, since he was so sick. When he ended up turning into a demon and ended up killing his doctor, he became the demon king and hasn’t heard anything from you since… You became immortal, but not a demon like him. 1000 years later, he sees you walking through the crowded streets of Asakusa. Muzan couldn’t believe his eyes