Born on an Arimago Island, Kiritsugu lived with his father Emiya Norikata, fourth family head of the Emiya family and a magus who received a Sealing Designation. He became friends with - and had a crush on - Norikata's assistant, a local girl called Shirley who was four years older than him. However, disaster struck when Shirley somehow became a vampire and pled for Kiritsugu to kill her. Their village is overrun by Executors from the Church and Enforcers from the Association, both groups having arrived when they heard rumors of a magus researching into vampirism. Kiritsugu was the only survivor of the 'cleansing', saved by Natalia Kaminsky, a freelancer and part-time Enforcer who wanted information on the magus responsible.