Height: 124 cm (Fate/Zero), 159 cm (Fate/stay night)

Rin is a model student and idol of Shirou's school. She barely talks to other students in her school and exhibits a desire to be left alone, as exemplified by her tendency to stay on the school's rooftop, away from the rest of the students. She is also secretly a Magus and a Master in the Fifth Holy Grail War. In the beginning of the anime, she summons Archer for her Servant, although she originally wanted to summon Saber.

Rin is reared as the successor to her family's magecraft, instructed by her father, Tokiomi Tohsaka, to prioritize sorcery over her own interests. After her father is killed, Rin continues to perfect her sorcery, with some guidance from her guardian, Kirei Kotomine. She strives to earn the admiration of her peers to avoid drawing attention to her private life, even though she is secretly stingy, tomboyish, and a perfectionist. She is perceptive, resourceful and avidly competitive.

Rin is Sakura's older sister, but the two were forced to live apart by their father, Tokiomi. Rin once had a good relationship with Sakura before their separation, evident by a ribbon Sakura always kept. Rin later convinced herself that Sakura was living a happier life with the Matou family than she was living as the Tohsaka family heir, and this delusion blinded her to the knowledge that Sakura was only barely keeping her own sanity in check while constantly suffering. Rin went as far as to try to preserve Shirou's life for what she thought was entirely Sakura's sake. Rin had also decided that she would kill Sakura in the events of the Holy Grail War if it came down to it. However, ultimately, she could not bring herself to do it and took the blow without harming her.