He serves as one of the antagonists in the game.

Heihachi is the host of this tournament.

From Tekken Tag Tournament 2 until Tekken 7, he was voiced by Unshō Ishizuka who later passed away on August 13, 2018.

Heihachi was voiced by Daisuke Gōri prior to his death on January 17, 2010, from Tekken 3 to Tekken 6, by Banjo Ginga in Tekken and Wataru Takagi in Tekken 2.Heihachi's fighting style is heavily based on Okinawan karate styles such as Shorin-ryu and Goju-ryu.The style utilized their animalistic traits as well as drawing on some of Heihachi's own moves. As well as taking over as head of the Mishima Style Fighting Karate after imprisoning his father, Heihachi also created the style Kuma Shinken and trained bears to fight using it.Mishima ( 三島) is the family name of all Mishimas and means 'third island'.It can be read as hachi, hatsu, ya, yattsu or yō. All Mishima given names end with the kanji '八' (meaning 'eight').

Heihachi ( 平八) is literally 'flat eight' in English.' Come back when you're ready to fight!' (after defeating his enemy).' So this is the King of Hell? You are nothing compared to the King of Iron Fist!' (against Lucifer).' Kazumi.' (against Kazumi or Devil Kazumi).' That infernal blood of a devil!' (against Demonic Charlie, Kazuya, Devil Kazuya, Jin, or Devil Jin).' Do you think you're tougher than me?'.To take over hell, they have to kill all of the Overlords, the Hazbin Hotel staffs, and the Manji Clan, Shadaloo, and Shirai Ryu members, as their main targets to gain their powers, but somehow Raven and the demon hunters find out what they are planning to, so they also attack the demon hunters and the Pentagram Police Department officers for investigating the case of what they are planning to.

Later, Heihachi opens the King of Iron Fist Tournament while they plan to obtain the Devil Gene and to take over Hell with intention of achieving world peace under their rules. Sir Pentious then became excessively supportive to him and Heihachi offers Pentious to join the Mishima Zaibatsu, then Pentious decided to join it and was claimed to become Heihachi's trusted bodyguard, while Vader, who owns Galactic Empire, started collaborating with the Mishima Zaibatsu. Years later, Heihachi Mishima was brought back to life by Sir Pentious along with the Egg Bois and Darth Vader. Members of G Corporation, Grove Street, Manji Clan, Shadaloo, and Shirai Ryu

Heihachi mishima tekken 3