Saber is one of the main characters in Fate/Zero, and one of the three main heroines in Fate/Stay Night, along with Rin Tohsaka and Sakura Matou. She's the Saber Class Servant of Kiritsugu Emiya in the Fourth Holy Grail War of Fate/Zero, and the Saber Class Servant of Shirou Emiya in the Fifth Holy Grail War of Fate/Stay Night, Kiritsugu's adopted son.