Heihachi's story and traits are based on Harada's history with his father. Harada was born in 1970, after World War II . However, Harada claims that in that period, parents were harsh with their children in Japan. As a result, Heihachi was portrayed as an antagonistic father to his son; something that the Japanese players could relate to. Heihachi's power in the form of the zaibatsu was based on the Imperialistic Japan. Furthermore, Heihachi is Tekkens personification of wartime Japan. After Tekken 6, Heihachi's voice actor Daisuke Gōri passed away. In order to include the character once again in the spin-off Tekken Tag Tournament 2, Namco hired a new voice actor who would fit into the character. As for in this game, Heihachi took a potion to make himself look younger. The voice selected was Unshō Ishizuka. Tekken 7s story mode was supposed to conclude the long struggle between Kazuya and Heihachi. However, Namco made the story so that newcomers to the franchise would understand it more easily. In further teasers of the game, Harada stated that in Tekken 7 Kazuya or Heihachi would die in their final fight. In 2016, Harada commented he had his own family. As a result, he compared it with the violent characters from Tekken who are constantly fighting each other: Heihachi, Jin, and Kazuya. He viewed this type of family as "too hard" in comparison. When asked about the final fight between both Kazuya and Heihachi, Harada called it "a major milestone in the storyline", as he was surprised by how extended the rivalry between these two characters has become due to the franchise's current popularity, and thus felt it was necessary to end this in a mortal fight. In Tekken 5, his movesets were viewed as one of the strongest from the cast but GameSpy commented that he lacked a weakness, as well as quicker attacks. In preparations for Tekken 7, Harada commented that he would often try Devil Jin if he was an "intermediate player", comparing his skills with Heihachi's. For Capcom's crossover game Street Fighter X Tekken, the official guide noted how Heihachi's multiple combos could inflict a large amount of damage on the opponents. For the film Tekken: Blood Vengeance, writer Dai Satō commented that he had to wait to get Namco's approval to introduce Heihachi's final transformation using the power of the Mokujin in order to fight Jin in