Fate/Prototype

Ayaka Sajou was born into a distinguished family of magi and should have been prepared to enter the Holy Grail War. Instead, the previous conflict took both her father and her older sister, leaving Ayaka frightened, withdrawn, and determined to stay away from the ritual that destroyed her family.

The war does not allow her that choice. When a Servant attacks and corners her, Ayaka instinctively summons a Saber of her own and becomes a Master. Protected by the knight she never intended to call, she is forced into a new Holy Grail War where the past she has avoided, the expectations of her bloodline, and the identities of the other Masters can no longer be ignored.