Rin is shown to have light blond hair similar to Rai (although slightly longer in length) and violet eyes. Her outfit is identical to her twin brother - having a red trenchcoat, a white shirt with a matching pair of pants and a black belt. Rin also wears a pair of sunglasses that has a cat eye design on her left.
In episode 34, it is revealed that Rin was chosen among thousands of applicants along with Rai, and the Shinomiya twins were received special training from the Manganji Laboratory. She is one of the possible contenders of Jirou in the Asia Cup finals, but Rai is the one who is competing against Jirou instead.
Rin is paired with Rai during the first stage of the World Cup, where the Manganji Dreams encounters the Great Rocky and the Mulegends team. She eventually makes her way to the tournament's third stage as one of the contestants for the semifinals. Rin is later eliminated by Kuroudo during her match against him being the second member of the Manganji Dreams to ever lose after Dan Midou. It is unknown if Rai was either defeated or forfeited.
- Rin's physical appearance resembles that of Android 18 from Dragon Ball Z.
- Rin's gender is changed to male in the German dub of the anime.
- Rin is the only female contestant in the World Cup quarterfinals and the only female member in the entire Manganji team (the club and its subdivisions).