Also known as: レイセン, レイセン2号, Rei’sen, Reysen
Not to be confused with Reisen Udongein Inaba, Reisen is the Watatsuki sisters' pet in Silent Sinner In Blue, a manga spinoff of Touhou Project.
Named after Reisen Udongein Inaba. Sometimes referred to by fans as "Reisen II" (レイセン2号) to distinguish her from the original, but English-speaking fans also use the unofficial romanization "Rei’sen" with the an added apostrophe or alternatively the anglicized phonetic spelling "Reysen".