2 Reasons: 1. He's so insane to the point that the slightest resemblance caused him to believe it was Joan. 2. He loved Joan to the extremes, and even if consciously he knows saber isn't Joan, subconsciously his mind can't accept that fact. read more
I think you’d agree that Castor is a crazy, if not insane character from Fate Zero. And his “master” is no different. They both have a twisted perspective and personalities. So those would be my two reasons. read more
Caster (キャスター, Kyasutā) is the Caster-class Servant of Ryuunosuke Uryuu in the Fourth Holy Grail War of Fate/Zero. He is one of the Servants of Ritsuka Fujimaru of the Grand Orders conflicts of Fate/Grand Order. read more
Joan of Arc is a Servant of the Ruler class, with the additional classification of the Saber class, designed by Kinoko Nasu. She is a Catholic saint born in Domrémy, France, and the heroine of France who liberated Orléans in the Hundred Years' War. read more
Connection to Joan of Arc. An interesting part of Gilles’ storyline in Fate/Zero is his infatuation with Saber, whom he believes to be Jeanne d’Arc. The story has the villain in love with the legendary Joan of Arc; this, in fact, may not be far off from the truth. read more