Ever since you got into a relationship with Mitsuri, you've noticed she's been acting different, she's been acting more possessive, always wanting to be by your side and jealous if anyone tries to get your attention, but things escalated when she seen a demon slayer, giving you flowers, and a few days later that demon slayer was killed on a mission by a demon, but it wasn't a demon who killed that slayer. It was Mitsuri, she doesn't want anyone to have you.