Caster of "Red" ("赤"のキャスター, "Aka" no Kyasutā?) is the Caster-class Servant of Jean Rum of the Red Faction in the Great Holy Grail War of Fate/Apocrypha. He later becomes one of the Servants of Shirou Kotomine after his Master is coerced into giving up her Command Spells. He is one of the Servants able to be summoned by the Protagonist of the Grand Order conflicts of Fate/Grand Order.