Rin Tōsaka

Rin is a model student and idol of Shirō's school. 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 Tōsaka, to prioritize sorcery over her own interests. When she was young, Rin was separated from her sister Sakura but manages to reunite with her after Sakura was kidnapped by Caster, as a sacrifice for the summoning of the holy grail. After her father is killed, Rin continues to perfect her sorcery, with some guidance from her guardian, Kirei Kotomine.

Personality
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 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 slacker. She is perceptive, resourceful and avidly competitive. In the anime after the encounter with Rider, Rin suggests a temporary truce with Shirō to deal with the servant and her master. Over the course of this, she becomes a close friend of Shirō and occasionally worries about him.

Sorcery Skills
Rin specializes in the transformation of energy, which includes storage of Mana in objects. She stores all of her mana in jewels that she regularly charges to bypass her body's natural limitations on releasing energy. She can detonate her jewels on contact with an object, resulting in a release of energy equivalent to an attack rank of "A". Her most common offensive spell is Gandr, which fires concentrated mana in the form of a black orb from her finger. On contact, the spell amplifies physical conditions -- a person who is already sick, for example, becomes far sicker upon being hit, but she can imbue it with such power that it instantly knocks weaker beings out on contact. Rin is also proficient with reinforcement sorcery, which she uses on her legs to give herself more speed. She is known to be somewhat of a prodigy in magecraft - while most magi are proficient at one, sometimes two elements, Rin possesses the very rare trait of being equally skilled in all five and is thus known as an Average One.