Eddy failed to win The King of Iron Fist Tournament 5. He pleaded with Jin--who had become the new head of the Mishima Zaibatsu--to help him save his mentor. Jin agreed to help develop medical treatment for Eddy's mentor in exchange for Eddy reporting directly to him as a part of the Tekken Force. Eddy knew nothing about the Tekken Force other than the fact that it was a private military outfit, but he agreed to join if it would save his mentor.
At once, Eddy became a member of the Tekken Force and carried out the Mishima Zaibatsu’s plans of destruction around the world. Even though he knew the consequences of his actions, Eddy was unable to leave the Tekken Force. When the Mishima Zaibatsu announced The King of Iron Fist Tournament 6, Eddy joined the tournament as a member of the Tekken Force in order to eliminate those who would threaten Jin.