John Kramer, also known as the Jigsaw Killer, is a fictional character from the Saw horror film series. He is a former civil engineer who becomes a notorious serial killer after being diagnosed with terminal cancer. Instead of killing his victims outright, John creates elaborate traps that test their will to live, forcing them to confront their life choices. Despite his gruesome methods, John believes he is teaching valuable lessons about appreciation for life. His character raises questions about morality and justice, making him a complex figure in horror cinema. The Saw series explores the psychological aspects of fear and survival through his twisted games.