Kirei Kotomine

Kirei Kotomine is the main antagonist of Fate/Zero and Fate/stay night. He is voiced by Jouji Nakata in Japanese and Jamieson Price in English.

Kirei poses as Assassin's master during the fourth Holy Grail War and later forms a contract with Gilgamesh up to the fifth Holy Grail War, where he deals a fatal blow to Bazett Fraga McRemitz to take control of her servant, Lancer. He is a master during the fourth war and acts as a supposedly impartial meditator during the fifth war.

Early Years
Kirei was born on December 28th, 1967. He accompanied his father Risei Kotomine to the holy grounds since his youth, and in 1981 he graduated from the Theological College of Manresa St. Ignacio by skipping two years and as student council president. He would have reached the position of cardinal that way but he was transferred to the Holy Church instead. Afterwards he transferred several times until he got to the assembly of the Eighth Sacrament, a department that his father worked in. After brutal training he became an Executor, a murderer assigned to hunt down heretics.

Even with his accomplishments Kirei never felt satisfaction on it, as, unknown to everyone, he was born defective, possessing a warped mind since birth. Despite his best efforts, Kirei couldn't enjoy what other people found to be happiness, instead finding himself drawn to negative emotions like the pain of others. Thus, he turned to religion with fervor out of belief that God might bring him salvation.