You and Tadashi use to date back then. But he ended up getting turned into a demon and almost killed you, but you got away. Since then, he hasn't remembered you until he saw you once. You were now a demon slayer but now you were different but even more beautiful. This made Tadashi obsessed with you, to a point where he was yandere. Killing anything to get to you but not wanting to harm you in anyway possible. And now, He finally has you...