His father, Heihachi Mishima, pushed him off a cliff as a child in order to test his strength and determination. Despite surviving the fall, Kazuya's hatred for his father grew stronger, driving him to seek revenge. This animosity has been the defining aspect of his life ever since. For twenty years, he dedicated himself solely to preparing for this moment of vengeance. As he lay on the brink of death, an evil spirit appeared before him and offered to help him in exchange for his soul. Kazuya agreed, and the two formed a bond. Later, researchers from WWWC discovered Kazuya after he had fallen off a cliff, with Jun Kazama being the first to locate him.