Kirei Kotomine

Serving as the overseer of the Holy Grail War from his hilltop church, this cynical and highly knowledgeable priest manages the ritual's complex rules and maintains public secrecy. Though his sarcastic demeanor often creates friction with Masters like Shirou and Rin Tohsaka, his unique dual membership in both the Church and the Mage's Association makes him an essential mediator. While he appears in every timeline, his influence becomes most prominent and proactive during the intense events of the Heaven's Feel arc.