Heihachi Mishima

Heihachi Mishima (三島平八 Mishima Heihachi) debuted in the first game of the series and he has returned for all subsequent titles. His given name in Japanese (三島 平八) translates to "Flat Eight" in English. All Mishima given names end with the kanji　八　(meaning eight) pronounced as "Ya", "Pachi", or "Hachi".

Heihachi was born as the heir to the rich, powerful, and well-respected Jinpachi Mishima, the owner of the powerful Mishima Zaibatsu and a world-famous martial arts master. During this time, He fathered a son named Kazuya. Heihachi raised Kazuya harshly. Much to his chagrin, Kazuya grew up kind and frail, perhaps due to the more loving treatment he received from his grandfather Jinpachi (see Kazuya's Tekken 5ending). At some point, Heihachi betrayed Jinpachi and stole the Zaibatsu from him. 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. After assuming control, Heihachi began to steer the Zaibatsu into the military industry. Jinpachi attempted to launch a coup to retake the Zaibatsu from his son, but failed and was ultimately imprisoned underneath Hon-Maru where he remained for over 40 years until the events of Tekken 5.

Finally fed up with Kazuya's "weakness", Heihachi tossed his son down a deep ravine, claiming that if he were truly his son, he'd be able to survive the fall and climb back up. Kazuya actually managed to do so, but only through making a pact with Devil and instilling the Devil Gene in his blood was this possible. To further motivate Kazuya, Heihachi adopted the Chinese orphan Lee Chaolan and he raised him as a rival to his true son. It's assumed that Heihachi didn't care about Lee at all and only used him to irritate Kazuya. Over the years, Kazuya traveled abroad and competed in martial arts championships, becoming an undefeated champion (the only blemish on his record being a draw against Paul Phoenix). Eventually, Heihachi decides to test his son's strength and worth and announces the King of Iron First Tournament.

However, Heihachi is unexpectedly defeated by a powerful Kazuya in an intense father-son battle. In an act of revenge, Kazuya tosses an unconscious Heihachi down the same cliff that he was thrown off as a child. Heihachi manages to survive through sheer willpower and trains in solitude for the next two years until the King of Iron Fist Tournament 2 is announced. He enters to exact revenge his son and defeat him once and for all. The two face off in a final showdown which ends in Kazuya's defeat. To ensure his son's death, he tosses him into a volcano and leaves him for dead, believing him to be gone for good.

Fifteen years after the King of Iron Fist Tournament 2, Heihachi is approached by a young Jin Kazama, who claims to be his grandson. Heihachi takes him in and teaches him Mishima Style Karate for his own selfish purposes, planning to use him as bait for Ogre. Heihachi also notices that Jin possesses the same "dangerous power" as his son and resolves to eliminate him once he has served his purpose. He announces the King Of Iron Fist Tournament 3 in hopes of bringing together the most powerful fighters from across the globe to lure and capture Ogre.

During the King of Iron Fist Tournament 6 (which he secretly entered), he was defeated by Lars, who is later revealed to be his illegitimate son.

Heihachi is considered by most fans an "anti-hero"; not being as evil as Kazuya but, still having a dark side. At times, his actions are cold-hearted and sometimes, they are inspirational (having survived every attempt on his life thus far from pure willpower). In general, Heihachi is not above betrayal, deceit, or committing small crimes in pursuit of what he perceives as a "greater good". Blood relation means nothing to him. Once he has identified a threat, he will eliminate them without any hesitation.

Heihachi is basically the epitome of a self-made man. He believes in complete self-reliance and in being the best in every endeavor. The only charity he will give or alliance he will accept is when it benefits himself. When Kazuya proved too stubborn, he resorted to drastic measures; an action that has come back to bite him on several instances. Occasionally, he will reward people that he deems as extraordinary. For example, he adopted Lee Chaolan after witnessing the orphan fighting, he took in Jin Kazama and actually came to respect his determination to defeat Ogre, but decided to eliminate him. He also admitted Ling Xiaoyu into his school (complete with a giant panda bodyguard) after she aggressively attacked one of his yachts.

Despite coming off as a gruff man, rewarding those who win his respect, but still willing to manipulate his loved ones and family members in order to achieve his plans, Heihachi is not without a heart. Despite Kazumi's supposed death, Heihachi still loves her dearly. When confronted by his son years later, he sheds a tear when his son shouts that Heihachi had killed Kazumi. This indicates that Heihachi and Kazumi had a blissful relationship and that Heihachi may have been more reluctant or regretful over Kazumi's death more than his son could've known.

It's not yet known why Heihachi has become so interested in creating an "ultimate life form" by combining the DNA of himself, Ogre, and the Devil Gene. It can be assumed that because he no longer wishes to succeed his company to either Kazuya or Jin, that the best he could do would be to clone an heir and ensure that it would be worthy. Another theory is that he wants to find a way to use Ogre and the Devil Gene to make himself an immortal, thus making an heir unnecessary. A third theory is that his interest may simply have something to do with his desire to take over the world using these lifeforms.