Otane Goketsuji is a reoccurring character in the Power Instinct series, appearing in the first and second installment. In Groove On Fight, she appears as a playable duo fighting alongside her older twin sister, Oume. Otane is mysterious and secretive, much like her sister, Oume. Otane had a very sad childhood as she was abused by Oume growing up. When Otane was 6 years old, she returned home very tired one day. As soon as Otane closed her eyes, Oume betrayed her and confined Otane in a box before throwing it into the sea.

Some time later, the box was found by a farmer who heard crying from inside the box. The farmer took Otane home to stay with his family, but due to the traumatic event Otane could only remember her name. Otane lived with the farmer's family for seven years. After finding out about her past, Otane sought revenge against her sister. Due to her unconquerable spirit, Otane has become superhuman.