Fate Series・Key Chains・Rin Tohsaka

Fate is a media franchise developed by Type-Moon that originated with the release of a PC-based adult visual novel called Fate/stay night in January 2004. A version of Fate/stay night rated for ages 15 and up titled Fate/stay night Realta Nua (Irish for "new stars") was released for the PlayStation 2 and later for download on Windows, as a trilogy covering the three main story lines. The Fate series follows various battles called Holy Grail Wars that involve Masters, Servants, and Heroic Spirits. Since Fate/stay night, the franchise has produced many prequels, sequels, spin-offs, and adaptations under the Fate umbrella in the forms of visual novels, manga, anime, light novels, video games, and more.

Two centuries ago, the Tosaka House, in collaboration with the estates of Makiri and Einzbern, helped found the Fuyuki Holy Grail Wars. The land of Fuyuki City, which possessed the second greatest spiritual power in all Japan, was owned by one of Rin's ancestors, Nagato Tosaka. At the behest of the Einzberns, he provided his property as battleground for present and future wars. Nagato was a kirishitan, as well as a pupil of Zelretch. These titles gave him considerable influence in both the Mage's Association and the Church, allowing the Tosaka family to participate in the Holy Grail Wars free from harassment by either organization. Rin was brought up as the successor to her family's magecraft and was instructed by her father to prioritize magecraft over her own interests.

Rin is a perceptive, serious, resourceful and very competitive person. Though she is widely admired at school as a prim and proper honor student, it is a front she puts up in order to prevent others from prying into her life. In private, she is notably loud, shrewd, stingy, and bossy. However, she usually has the best of intentions when it comes to people she cares about. She is known as a model student and idol at her school. Her manner of speech is often hostile and dismissive of other people but deep down, she has a caring heart. Her tendency to make trivial mistakes at the worst possible moments is a hereditary curse. Though she really is a lot nicer than she seems, she claims to always make her decisions based on cold, rational logic in the end. In her own words, it's "not a very cute personality." Despite claiming that she would do anything in order to win the Holy Grail War, no matter how underhanded, she actually has a deeply rooted sense of honor.