Mishima Zaibatsu is a giant powerful multinational conglomerate, and an evil organization and the main antagnactic coportion of the Tekken series. Every winners of The King Of Iron Fist Tournament, will receive a huge portion of money, but in Tekken 4 the prize was to be crowned as the new owner.
Mishima Zaibatsu or Tekken Zaibatsu (name changed after Jinpachi Mishima lost the Zaibatsu to his son), it was owned originally by Jinpachi, but the Zaibatsu was taken over by Heihachi, who has run the company for over 40 years, except for two brief interims. The companies grouped together in the syndicate include the Mishima Financial Empire, the mercenary group known as Tekken Force, and Mishima Industries. The Mishima Zaibatsu is the main sponsor of The King of Iron Fist Tournaments, the central events of the video games. In Tekken 5, Jinpachi Mishima regained control of the Mishima Zaibatsu. However, Jinpachi was defeated by Jin Kazama during The King of Iron Fist Tournament 5, and Jin gained control of the Zaibatsu in order to find a cure for his Devil Gene. Jin declared the Mishima Zaibatsu’s independence and waged war against the rest of the world to destroy an even greater evil capable of destroying the world.
The Mishima Zaibatsu swept across the globe, taking over nation after nation. But as the war continued, new opposing forces slowly began to show their presence. Jin learned that Kazuya Mishima was controlling the first and most powerful opposition, the G Corporation. When the G Corporation placed a price on his head, Jin announced The King of Iron Fist Tournament 6, as if he had been waiting for the G Corporation to make its move.
However in the Scenario Campaign mode it is revealed that the war and tournament was just to fill the world with enough negative energy to make the physical form of the evil entity known as Azazel, because Kazuya and Jin are known as the "Two Evil Stars".
- Jinpachi Mishima: Founder and leader of Mishima Zaibatsu until his son Heihachi overthrow him. Becomes leader again in Tekken 5 until he was defeated and destroyed by his great-grandson Jin Kazama.
- Heihachi Mishima: Leader in Tekken, Tekken 3, Tekken 4, and Tekken 7. Founder of the Tekken Force. Overthrown once by his son Kazuya at the end of Tekken and was usurped by his father Jinpachi during his disappearance in Tekken 5. Recently regained control of the Zaibatsu after the dissapearance of his nephew Jin. He's continuing the war against G Corporation (perhaps not against the world like Jin in Tekken 6).
- Kazuya Mishima/Devil - Leader in Tekken 2 and business partner of various criminal organizations, after defeating and almost killing his father Heihachi in Tekken. He was overthrown again by his father and killed 2 years later. He was revived a few days later and joined with G Corporation, serving as the most important text subject for 20 years. He is now the current leader of G Corporation.
- Jin Kazama/Devil Jin: CEO in Tekken 6: After defeated Jinpachi in the King of Iron Fist Tournament 5, he takes over the Mishima Zaibatsu and declared a war against the rest of world in order to destroy the world and filling it with negative energy. He also opened the King of Iron Fist Tournament 6 in order to kill Kazuya Mishima and crush his organization (G Corporation).
- Nina Williams: She recruited by Jin to be his bodyguard and assist his Tekken Force in taking over the world. With strong tension between the Mishima Zaibatsu and G Corporation, the King of the Iron Fist Tournament 6 was announced. In order to remove any threats to the life of Jin Kazama, Nina enters the tournament.
- Eddy Gordo: Eddy was failed to win the King of Iron Fist Tournament 5. He spoke alone with Jin. Jin offered to lend him his money and resources to save his master's life. If Eddy joined the Tekken Force, he promised to find a cure for Eddy's master's illness. Eddy joins the Tekken Force, and he is involved with a number of criminal operations just as The King of Iron Fist Tournament 6 approaches.
- Alisa Bosconovitch: Alisa's journey begins when a man named Lars awakens her out of cryosleep. Suddenly, G Corporation's Jack-6 robots attack both Alisa and Lars. Alisa retaliates by using her chainsaws to saw off a JACK robot. Then, later in the game mode, they meet Lee Chaolan who is the foster brother of Lars Alexandersson. Lee is a major shareholder of G Corporation and a huge part of its robotic equipment came from Violet Systems. Because he knows better about his adoptive relatives, Lee is against Kazuya Mishima and G Corporation, just like Lars and Alisa. He's also against the Mishima Zaibatsu, as Jin Kazama is damaging Lee's personal gain. Near the end, it is revealed that Alisa was built to protect Jin Kazama. Alisa betrays Lars and later a big battle occurs, Lars then fights Jin Kazama. His nephew explains about the chaos he started around the world. It was a theory by a woman named Zafina. She said that Jin Kazama and Kazuya Mishima are the two evil stars of the Devil Gene to awaken Azazel. They both came into combat contact, awakening his spirit. He said that he must put an end to the Mishima Bloodline and save the world from Azazel's existence. Suddenly, Golden Azazel emerges in front of Lars and Jin.
- Dr. Abel: Rival of Dr. Bosconovitch and enemy of G Corporation, as well as personal enemy of G Corporation's scientist Jane. Mostly known as the reviver and creator of Bryan Fury Mishima's top scientifical advisor, Heihachi's right hand, and leader supervisor for the Zaibatsu's Devil Gene Program since the events after Tekken 3. Abel conducted experiments on living beings for Heihachi. He also took control of the G Corporation's forest rejuvenation project, called GENOCELL, lead by a team of scientist and researchers (including Julia Chang), after Heihachi had 2 of G Corporation's security labs raided (in Nepal and Nebraska) and valuable data was stolen from the G Corp scientists. Under Heihachi's orders, Abel and the other scientists used the GENOCELL research they had stolen to aid one of their own projects; the merging of devil cells with human cells. Abel's current status is unknown.
- Lee Chaolan: Heihachi's heir and right-hand and scientific supervisor in Tekken. Kazuya's secretary and scientific supervisor in Tekken 2. Expelled by Heihachi for betrayal. Currently the CEO of Violet Systems and indirect supporter of the rebels of G Corporation against the Mishima Zaibatsu.
- Kuma I: in Tekken and briefly after Tekken 2. Heihachi's bodyguard and man-eater. His status has never been fully revealed by Namco.
- Kuma II : Kuma I's son. Heihachi's bodyguard in Tekken 3 who defected after the game to lead other wild bears in Hokkaido. Candidate as the new leader of the Zaibatsu in Tekken 5. Tekken Force operative and Heihachi's bodyguard in Tekken 7.
- Anna Williams: Kazuya's bodyguard in Tekken 2. Currently an enemy of the Zaibatsu, serving a member of G Corporation, security leader of the Millenium Tower (G Corp's building), and acting as Kazuya's bodyguard again.
- Bruce Irvin: Kazuya's bodyguard in Tekken 2. Currently an enemy of the Zaibatsu, serving as G Corporation's main general and drill sergeant, and Kazuya's bodyguard again.
- Ganryu: in Tekken 2. Former Sumo wrestler and Kazuya's bodyguard. He now lives his own life as the owner of a sumo stable and a restaurant in Hawaii called Chanko Paradise.
- Lars Alexandersson: Prior Tekken 6, under Heihachi. Former Tekken Force officer and rebel leader during World War III. Expelled by Jin for betrayal. Lars had been working for the corrupted Heihachi and the possessed Jinpachi, acting obedient and neutral to his orders. It's possible that during Tekken 3 he went to the ancient Aztec ruins in Mexico with Heihachi when Ogre was freed and awakened, thanks to Heihachi's own greed for power, who had also kidnapped Michelle Chang and used her pendant to draw Ogre for capture and left Michelle for dead (she was rescued by Julia).
- Dr. Geppetto Bosconovitch: Former USSR scientist and creator of the first Jack robots, including prototypes. He was a neutral scientist who always supported the Mishima Zaibatsu. He served as an actual Mishima Zaibatsu scientist under Kazuya (forced to work) in Tekken 2. Currently works as a neutral scientist with no sense of good or evil and is still an ally to the Zaibatsu. He built the robot Alisa Bosconovitch as his deceased beloved daughter. He programmed in Alisa's system to search her father and serve Jin Kazama. He also created Roger and Alex and "re-created" Bryan Fury. He also saved Yoshimitsu's life, by turning the former human being (cursed by his own evil sword and also wounded by Mishima men) into a cyborg during the years, and is now almost a complete robot. Jack-2's programming was stolen by Jane (who first created Gun Jack) and G Corporation has now an army of improved Jack robots.
- Dr. Emma Kliesen: Scientist of the Zaibatsu during the years between Tekken 2 and Tekken 3. Apparently she had been a supervisor for the Mishima Zaibatsu's Devil Gene program. The program was cancelled due to the death of it's test subjects. Emma had also falsely reported the death of NT01 (Steve Fox). She was murdered between Tekken 5 and Tekken 6 by either Kazuya Mishima and Bruce Irvin, who murdered all the leaders of the Corporation (Kazuya for revenge, Bruce for fun).
- NANCY-MI847J: Jin's robot and protector. The "MI" stands for "Mishima Industries", "847" is its model number, and "J" stands for Japan. Nancy Dietrich was the director of designing the MI series of robots. She and several others were killed in a G Corporation attack by Jack-4's during Tekken 5. The robot's name was taken after this director.
- Prototype Jack: Kazuya's attack robot in Tekken 2. Created by Doctor Bosconovitch prior the events of the series.
- Roger and Alex: Both the results of a military experiment in the (now closed) old Mishima laboratory under Kazuya Mishima. Doctor Bosconovitch wanted to combine the genes from a martial artist and cross them with wild animals. Doctor Abel had stolen Roger and Alex and kept them with him in his secret laboratory. They were both set free in Australia by WWWC officer Jun Kazama.
- While the Mishima Zaibatsu is always presented as a villainous organization, G Corporation is no better. Like the Mishima Zaibatsu they murdered several enemies and conducted (and keeps doing it, with Gigas in Tekken 7 as an example) amoral scientific experiments of mutation and cloning on countless human beings, before locking them in abandoned laboratories. In the Devil Within minigame, G Corporation built another laboratory upon Ogre's ancient ruins. All the scientists (named among them are Bosconovicth, Abel, Jane, and Emma Kliesen) in the Tekken universe are considered morally ambigous and are responsible for villainous creations and acts.
- The corporation along with G Corporation are considered to be much more powerful than any governments in the world as they can cause a massive world war without much of the intervention from the UN.