A character in Catherine: Full Body, they were not in the original game.
Rin is one of the three love interests of Vincent Brooks in the game. In the game it is revealed later that Rin is a crossdresser. Even further in the game, Rin is also revealed to be actually an Alien disguised as a human for their mission.
They have short Pink Hair with Bangs and Blue Eyes. They wear a sleeveless blue Sailor Dress with frills on the ends.