Shinji Matou (間桐 慎二, Matō Shinji?) is the acting Master of Rider in the Fifth Holy Grail War of Fate/stay night. He is merely using the Servant of his adopted younger sister, Sakura Matou due to his inability to use magecraft. He has been a friend of Shirou Emiya for a number of years. He has an open crush on Rin Tohsaka, but she does not return his interest, much to his frustration.

Shinji is arrogant and impulsive. Initially he considered himself to be special when he discovered the Matou were a clan of magi and began putting all of his heart and effort into becoming one himself, only to later find they were a fallen clan who no longer had magical power, and that Sakura was going to fullfil his lifelong dream. He also feels entitled to things that he believes both the world and his family denied him, and will do anything to get recompensated. Due to his arrogance and inferiority complex, he refuses to admit that Shirou and Sakura are the only ones that care for him and believes it must be pity instead.[3]

Though he is selfish and has the bad habit of looking down on other people, he has some faintly redeeming qualities. He values rules (but he does not follow them himself), and he hates injustice (if he's not the one responsible). Due to the gap between his "ideal world" and the world he actually lives in, his personality has become warped, but when Shirou first made his acquaintance four years ago he was not nearly as bad as he is now.[2]