Pet lunar rabbit of Houraisan Kaguya, apprentice to Yagokoro Eirin, and caretaker of earth-born rabbit youkai Inaba Tewi. Her power is to cause lunacy with her stare, as well as control all kinds of wavelengths. Ironically, Reisen is also depicted as one of the more level-headed characters of the series. Doujins make fun of her danmaku, which vaguely resemble suppositories, as well as her rabbit ears, which look as though they were buttoned onto her head.
