Walter Sullivan is the main antagonist of Silent Hill 4: The Room. He was an infamous serial killer, killing at least nineteen people (including two children), and a religious fanatic, courtesy of the Order's beliefs being imposed upon him as a child. Attempting to fulfill a macabre ritual called the 21 Sacraments, his life's goal was to cleanse the world of its sins.
He show an odd empathy-lacking attitude towards killing. Also seemed unable to view his victims as anything beyond their roles.