However, the Sister actually was using the children living in the orphanage to commit crimes, controlling them via hypnosis she implanted during their counseling. While Ken was revisting after being reunited with a friend he knew from the orphanage, he met Nagi - and it was during this that Weiss received a mission to target Sister Amamiya. It was Ken who ultimately killed the nun. Nagi witnessed the murder, and as a result of his devastation, he made the church collapse by using his telekinetic powers. From there on he vowed to kill Weiss, and hated Ken in specific.