I am behind on WaHH. Kasen could have had her identity discovered by now for all I know but I always wanted her to be found out by losing her hair buns and immediately coming clean to Reimu and Reimu nonchalantly saying "You insult me. You think I could not feel your massive oni presence ever since day 1 you set foot at my shrine? I played along since I thought things could get more interesting but I would strike you down the very second I sensed any malice toward me or my friends." or something like that. I doubt that would happen since Reimu has been duped by even low ranked yokai.