|“||Foolish human, you would take my attack to save your feeble Pokémon!||”|
–Mewtwo in the film Mewtwo Strikes Back
As shown at the beginning of Mewtwo Strikes Back, Mewtwo has been created by a group of scientists led by Dr. Fuji. His companion in these early days was Ambertwo, a clone of Fuji's deceased daughter Amber who sadly perished much like the girl she was cloned from. After learning that the scientists regard him a merely an experiment and not as a living creature of worth he becomes filled with rage. He destroys the laboratory, and is approached by the arriving Giovanni with an offer to learn to control his powers. With some sort of armor on, Mewtwo is used in The Battle of the Badge against Gary Oak in a gym battle after aiding Giovanni in a series of other victories. Gary describes him as an "evil" Pokémon to Ash Ketchum, who doesn't get the chance to see it. Mewtwo escapes from Giovanni after finding out that they aren't partners, but that Giovanni regards him as a weapon. He levels Giovanni's mansion and destroys his armor in the process, and is seen briefly by Jessie and James in It's Mr. Mime Time!
Mewtwo Strikes Back
Mewtwo subsequently returns to his birthplace, New Island, and rebuilds the lab he destroyed into a massive castle. He kidnaps the Nurse Joy of the nearest Pokémon Center, and takes control of her mind. After gaining her help in preparing for his plan to create an army of Cloned Pokémon, he has her send invitation discs to some strong Trainers. The Trainers go through a storm that Mewtwo caused as a test, with the storm's true purpose being to wipe out all humans and those Pokémon not created through cloning as Mewtwo and his army were, as he considers natural Pokémon weak due to their willingness to serve or befriend humans. Once the trainers arrive, Mewtwo reveals himself, claiming to be both the world's strongest Pokémon trainer and the world's most powerful Pokémon.
After proving himself more than a match for several of the Pokémon assembled on the island, Mewtwo releases Nurse Joy from his control. He then accepts a challenge from Ash to prove the superiority of his cloned Pokémon, and unleashes cloned versions of Charizard, Blastoise, and Venusaur to challenge natural versions partnered with Ash and two of the other trainers. Upon achieving victory, Mewtwo captures all the trainers' Pokémon and clones them to create his army of clones, and informs the humans that he will spare them, but that they will be consumed by the storm like the rest of the planet. However, Ash then arrives with the freed natural Pokémon to challenge him, only for a far more startling opponent to appear: a living Mew.
Mewtwo challenges Mew to a battle, determined to prove that he is the superior Pokémon, which leads to a battle between the two and their respective groups of Pokémon. Using their psychic abilities, the pair suppress the abilities of the Pokémon under their leadership and engage in battle. Blind to the suffering of both sides, the two continue to clash until Ash rushes between them in a desperate attempt to stop the fighting. Their blasts render Ash inert in a stone-like state, from which he is revived by the tears of natural and cloned Pokémon alike. This sight enables Mewtwo to realize that it is one's choices, not the circumstances of their birth, that determines their identity. Dissipating his storm, he then departs with his clone army and returns the humans and their Pokémon to their proper places, erasing their memories of encountering him.
In Mewtwo Returns, the clones have found a lovely place to live, on top of Johto's largest mountain. They could live there in peace, but Giovanni finds them. In the end he departs the other cloned Pokémon so they can live peacefully as wild Pokémon.
Mewtwo's uniqueness largely stems from his psychic abilities, however, his personality is one of the defining points in the Pokémon series. Mewtwo's personality is initially complex involving existentialist anxiety, and contemplation of the meaning of existence. His temperament is very introverted, consisting of hate and anger towards humans and his creators.
Having been brought into existence through artificial means, Mewtwo quickly turned on his creators when he learned that they intended to experiment on him further. Feeling betrayed by the very humans that had created him, he decided to forge his own path. The recurring theme in the movies is Mewtwo harbors jealousy towards Mew because he is a copy or derivative whereas Mew is the original.
In the first movie, the path that Mewtwo has taken makes him into a rather immoral character. He frequently exhibits cruelty and at several intervals goes so far as to attempt to, or forthrightly, kill those who oppose him. He also shows no qualms about forcing Nurse Joy to serve as his puppet, and then casting her aside once she was of no further use to him. This makes Mewtwo easily one of the most malicious characters in the series and the main antagonist in Pokémon The First Movie, prior to his change of heart at the end of the first movie.
However, in Mewtwo Returns, he is much more kind. Mewtwo only wants to protect the other clones that he created, and even protected humans that were on a bus that got thrown around by strong winds. Therefore Mewtwo is a hero in his second movie, and a victim. When Giovanni comes on the mountain, Mewtwo is willing to sacrifice himself to save the other clones as well as Ash's Pikachu and Team Rocket's Meowth. Also, he constantly wants to avoid fighting, exact opposite to the way he was in the first movie.
So, it can be said that Mewtwo, upon Ash's sacrifice in Mewtwo Strikes Back, has become a hero instead of a villain. He continues to live in Johto and, as said by himself, "In shadows."
|Psychic (move)||The Battle Of The Badge|
|Barrier||Mewtwo Strikes Back|
|Counter||Mewtwo Strikes Back|
|Shadow Ball||Mewtwo Strikes Back|
|+ indicates this Pokémon used this move recently.*|
- indicates this Pokémon normally can't use this move.
- Masachika Ichimura (Japanese)
- Jay Goede (English; Mewtwo Strikes Back)
- Dan Green (English; Mewtwo Returns)