In an effort to become the greatest killing machine in history, X traveled the globe to learn and train with various combat teachers, slaying each after surpassing their skills and scarring himself in a ritual fashion for each life he took. He slew his appalled parents shortly thereafter, beginning a life dedicated to the killing arts. He subsequently spent years attempting to recapture the thrill of that experience through other pursuits but finally sought out death again when he placed his pet dog in an oven. The experience triggered his latent telepathy, forming a bond with the dying woman.
Born into wealth, the man known only as Mister X became fascinated with death as a child when he saw a woman get hit by a car.