Hm? Wait a minute... The moon's movement.... The moon's movement...? It can't be... Whaaa!? Menstruation....!!The Japanese term for menstruation (月経) consists of "moon" (月) and "[movement] route" (経[路]). I see... I understand now. If I can dig out some information about her menstrual cycle, that should let me to find a way to defeat her danmaku! That moon's movements cycle is a metaphor of this girl's own menstruation cycle...!I'll make sure to leave it exposed...Reimu was treated like a pervert. Your menstruation cycle.
