Having been brought into existence through artificial means, Mewtwo quickly turned on its creators when he learned that they intended to experiment on him further. Feeling betrayed by the very humans that had created it, it decided to forge its own path. The recurring theme in the movies is Mewtwo harboring jealousy towards Mew because it 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. It frequently exhibits cruelty, and, at several intervals, goes so far as to attempt to (or forthrightly) kill those who oppose it. It also shows no qualms about forcing Nurse Joy to serve as its puppet, and then casting her aside once she was of no further use to it. This makes Mewtwo easily one of the most malicious characters in the series and the main antagonist in Pokémon The First Movie, prior to its change of heart at the end of the first movie.