Renan: Return of an Ancient Evil is an adventure/platform game created by RenarioExtreme INC.
The story starts after the events of Renan and the Seven Destructuive Rulers, with Dr. Mewtwo's satelite released from his hideout planet, which was used to destroy Renan's true hometown, but instead hit a statue of a Dragonite resembling the Gold Master but with dark aura surrounding him. After hitting the statue, the satelite causes a big explosion, with a dark spirit flying up to Dr. Mewtwo's hideout planet, laughing evilly. Upon hearing this, the Gold Master gets serious and takes Renan and his friends to the Shine Emperor's palace. Meanwhile, the Shadow Lord is scolding Dr. Mewtwo for his previous failures to steal the Master Diamonds to turn the PokeMutant World into Mewtwoland and eliminating Renan and his friends, threating to replace him with a better minion. At the Shine Emperor's palace, the Shine Emperor told the story to Renan and his friends about the Shadow Lord's past. He once worked together with the Gold Master to keep the peace, but he was banished to hell for both his disobedience and thought of the Shine Emperor's stirct rulling method, and now wants to get revenge on both of the rulers of the PokeMutant World so that he could rule the world all by himself. He first gave the spirits to Renan and his friends, and then gave them the Mystic Diamonds, which turned out to be fake because Dr. Mewtwo and the Shadow Lord has already stolen them and replaced them with fake ones. So, Renan must find the real Mystic Diamonds so that he could stop Dr. Mewtwo and the Shadow Lord.
Renan - One of the PokeMutant World's most trusted warrior. He must collect the Mystic Diamonds which Dr. Mewtwo has stolen.
Hiroshi - Renan's best friend and sidekick. He is only playable in plane flying-related levels.
The Gold Master - Renan's adopted father and the co-ruler of the PokeMutant World. He guides Renan at the start of the game.
Rexar - Renan's short-tempered friendly rival. He is seen standing beside the Guardian Diamond, and can be talked to.
Lenan - Renan's long lost twin brother. In order to save the game, he must be talked to.
Sunshine - A gorgeous female Espeon and Renan's love interest. She is kidnapped again by Dr. Mewtwo to use her as a hostage, Renan must rescue her at the third boss.
The Shine Emperor - The ruler of the PokeMutant World. He only appears at cutscenes.
Dr. Mewtwo - A evil genius Mewtwo and Renan's arch-nemesis. His plans to take over the PokeMutant World and convert it into Mewtwoland always fail.
The Shadow Lord - The Gold Master's younger twin brother and former servant of the Shine Emperor. Because he was banished for his disobiedience and betrayal against the Shine Emperor, he plots to destroy the Shine Emperor and the Gold Master so that he could rule the world all by himself.
Axel - Dr. Mewtwo's most trusted minion. He appears in World 3 as a boss.
Metal Renan - A robot created by Dr. Mewtwo - He appears in World 2 as a boss.