In the begining, Rin was seen as a minor, always serving Saki where or whenever she is is, but over time her role has seemingly increased. While Rin is very loyal and caring to Saki, she is also very dutiful. These made her conflicted when Saki once ran away from home, and Rin was ordered to bring her back, even by force. But after Saki managed to settle things with her family, she and Rin were able to remain friends.
Rin is usually calm and very composed, and is perhaps one of the most mature character in the series, at least among the students, despite how few moments her character was explored without being together with her friends. Like Saki and most other girls, she is also not completely safe from the antics that surround Rito Yuuki, and naturally, she has a negative impression of him, but she has shown few instances of potential to understand him better and perhaps grow more patient with him. Throughout most of the series, Rin is hardly ever seen without accompanying Saki Tenjouin and/or Aya Fujisaki, and has interacted personally with very few other characters in the series. However, in To LOVE-Ru Darkness, she has caught the notice of Momo, who is considering adding her to the Harem Plan, hoping that Rin would open up to consider Rito as a love interest.