Walter Sullivan is the main antagonist of Silent Hill 4: The Room. He was obsessed with the Room 302 since he firmly believed that it was his mother. In order to bring her back to him, Walter decided to complete the Twenty-One Sacraments, which required twenty-one sacrifices, so he became a serial killer and murdered ten people before being captured. Then, he committed suicide, becoming the eleventh victim and performing the Ritual of the Holy Assumption, allowing him to live as multiple ethereal entities at once. With his new powers, Walter killed three more people before the beginning of the events of the game