
After assuming control, Heihachi began to steer the Zaibatsu into the military industry. His motives for this act are as-of-yet unknown, but it can be speculated that Heihachi disagreed with his lack of aggression and his "soft" treatment of Kazuya. At some point, Heihachi betrayed Jinpachi and stole the Zaibatsu from him. Kazuya grew up kind and frail, perhaps due to the more loving treatment he received from his grandfather Jinpachi. It is believed that his wife Kazumi died while giving birth to Kazuya or not long afterward. During this time, Heihachi married Kazumi and eventually had a son with her named Kazuya. Heihachi was born as the heir to the rich, powerful, and well-respected Jinpachi Mishima, the head of the powerful Mishima Zaibatsu and a world-famous martial arts master. He is the son of Jinpachi Mishima, the father of Kazuya Mishima and Lars Alexanderson, the adoptive father of Lee Chaolan and the grandfather of Jin Kazama, but despite this, the members of the Mishima family despise each other, with Heihachi's Tekken 5 ending suggesting he would like to kill all three of his closest relatives (father, son, grandson).


He is the owner of the Mishima Zaibatsu in the original Tekken, Tekken 3 and Tekken 4 and can be considered the main antagonist in the series, with many key story developments revolving around Heihachi or actions related to him. Heihachi Mishima is one of only four characters to appear in every single Tekken game thus far (the other characters being Yoshimitsu, Nina Williams and Paul Phoenix).
