Shirou Kotomine (シロウ・コトミネ, Shirō Kotomine?) is the Master of Assassin of Red in the Great Holy Grail War of Fate/Apocrypha and the Ruler-class Servant of the Einzbern Master‎‎ in the Third Holy Grail War. He later contracts with Caster of Red, Archer of Red, Lancer of Red, Rider of Red, and Caster of Black. He is one of the Servants able to be summoned by the Protagonist in the Grand Orders of Fate/Grand Order.