Mewtwo is a genetically engineered legendary Pokémon created from the DNA of the mythical Pokémon Mew. In the anime special Pokémon: Mewtwo Returns, which follows the events of the first film, Mewtwo has retreated from human society and taken on the role of guardian and caretaker for a community of cloned Pokémon that he created. No longer the vengeful being driven by anger and confusion, he has become a quiet, introspective figure who is deeply protective of the clones he considers his family. He chooses a secluded island in a pristine lake atop Mount Quena in the Johto region as their sanctuary, believing that the clones, because they were not born naturally, do not belong in the outside world and must live apart from humans.

Mewtwo’s personality in this story is defined by a profound sense of responsibility mixed with lingering doubt and sorrow. He is highly intelligent and philosophical, often contemplating the meaning of existence and the value of life. He speaks through telepathy and communicates with both humans and Pokémon. Though he has softened compared to his earlier rebellion, he remains cautious and distrustful of people, especially those who might threaten his charges. He is not openly hostile but is reserved and distant. When he first encounters Ash, Misty, and Brock again—people whose memories of him he had previously erased—he shows recognition but keeps his distance, observing them warily. His motivation centers on preserving the clones’ safety and peace; he is willing to use his immense psychic powers to protect them, but he also struggles with the fear that true peace may be impossible.

Key relationships in the special include his bonds with the cloned Pokémon, most notably a cloned Pikachu and a cloned Meowth, with whom he spends much of his private time, possibly reflecting the importance of their originals in his change of heart. He also interacts with Team Rocket leader Giovanni, who discovers Mewtwo’s hiding place and attempts to recapture him, forcing Mewtwo into a confrontation. Ash and his friends act as unintentional catalysts for Mewtwo’s further growth, and Mewtwo ultimately accepts their help in fending off Giovanni’s forces. The cloned Pokémon themselves look to Mewtwo as a leader and protector, and their loyalty tests his resolve to keep them isolated.

Throughout the story, Mewtwo undergoes significant development. He initially insists on hiding the clones from the world and even considers abandoning them to search for a place alone, but witnessing their determination to defend their home—and seeing that Ash and his friends genuinely care for Pokémon—leads him to a new understanding. In the climax, after being captured by Giovanni’s agent Domino and then freed with Ash’s help, Mewtwo uses his powers to stop the conflict, heal the wounded spring that was damaged in the battle, and teleport himself and the clones away. He earnestly thanks Ash and company and departs with the clones to live elsewhere as natural Pokémon in the wild. This marks a shift from isolationist guardian to one who accepts that the clones can find their own place in the world.

Notable abilities showcased in Mewtwo Returns include telekinesis strong enough to lift and move an entire bus, create a shield against attacks, and calm a storm. He can teleport himself and others across great distances, including the entire group of clones. He also displays telepathic communication, weather manipulation, energy projection, and the capacity to heal or restore a natural spring. He retains the ability to clone Pokémon using a device, though in this special he does not create new clones. His psychic senses allow him to monitor activity from afar, and he can sense the intentions of those around him. Despite his power, Mewtwo remains a tragic figure, carrying the weight of his artificial origin and the memory of friends who perished—echoed in his backstory of a lost friend, Ambertwo, that he no longer consciously recalls. In Mewtwo Returns, he finds a measure of resolution by choosing to release both the clones and himself into an uncertain but hopeful future.