Rio Kastle, known as Rio Kamishiro (神代かみしろ璃緒りお, Kamishiro Rio) in the Japanese version, is one of the main characters, appearing in the Yu-Gi-Oh! ZEXAL anime. She is the younger twin sister of Shark.[9] Rio is later revealed to be Marin (Merag (メラグ, Meragu) in the Japanese version), a member of the Seven Barian HI