Lee Chaolan, adopted son of Heihachi Mishima, actively seeks his adoptive father's approval to become heir to the Mishima Conglomerate within the narrative of "Tekken: The Motion Picture." To achieve this goal, Lee orchestrates multiple assassination attempts against his adoptive brother, Kazuya Mishima, employing assassins Nina and Anna Williams to eliminate Kazuya prior to the King of Iron Fist Tournament. These attempts consistently fail to kill Kazuya.

Lee oversees and participates in the Mishima Conglomerate's illegal activities, specifically conducting biological experiments on endangered animals to transform them into bio-weapons designated as R-Experiments. He views the tournament participants as test subjects for these bio-weapons.

During the tournament finals, Lee releases the R-Experiments—genetically engineered dinosaur-like creatures—onto the island to kill all competitors and prevent anyone else from winning. This action results in the death of Anna Williams, who is consumed by one of the creatures. Lee is aware the creatures attack indiscriminately, including individuals he knows.

After Heihachi explicitly denies Lee the position of successor, Lee initiates the island's self-destruct sequence. His intention is to eliminate everyone on the island, including Heihachi, Kazuya, the remaining scientists, and himself, ensuring he becomes the sole inheritor of the Mishima Conglomerate by default. This plan ultimately fails as key characters escape the island's destruction.