in Fate Zero, Episode 10 - Rin's Adventure shows how she was forced to move out of Fuyuki with her mother by her father in preparation for the 4th Holy Grail War, but runs away from home when her friend Kotone disappears like other children from her school and Rin attends the funeral of one of the children who were found mutilated in Fuyuki.
According to the Wikia for Kotone it says
It is implied that Kotone meets the same gruesome fate as most of Ryuunosuke and Caster's other victims during the novel. ... She is never referenced again afterward. The anime version of the events play out differently, as Rin manages to follow Ryuunosuke to a old building where he is keeping a number of children. She finds Kotone among them, and she manages to save them all by shattering the magecraft that was holding them in a trance. Kotone returns to school afterward with the other victims.
Now watching the episode i can see how saving Kotone spurs Rin to study more to become the Magus she becomes in Fate/Stay Night however i am wondering, what is considered Kotone's fate in the canon (loosely used considering) and if she dies in the canon how does this affect Rin's motivation for study?