The antagonist, Porky, was designed as a "symbol of humankind". Itoi associated the game's view of evil to the "fun and games" on the spectrum of "pranks" to "crimes", and likened its tone to the lyrics of the song "Reunion" by Kazuko Matsuo, where the subject falls in love with someone the world finds evil. Itoi compared how the characters come to realize their psychic powers with menstruation, and added that human physiology was "one of his themes". As such, players sweat when learning an ability, based on Itoi's belief of how physical struggle facilitates growth. He also included characters like the Magypsies and Duster (who has a bad leg) to show the value of having friends with different qualities. Some environments were added to serve specific purposes. For example, Osohe Castle was meant to show the scale of time and Tantane Island was designed to reflect the player's worst nightmares as similar to "Mother 2" "hallucinatory city", Moonside. Another of his themes was the duality of the seriousness and lightheartedness of games, which is why he added a serious death scene to the first chapter. Other parts of the game referenced media such as "Kiki's Delivery Service". Itoi wrote the game's ending while overseas in Saipan before "Mother 3" was cancelled. His Nintendo 64 version was darker, "dirtier", and more upsetting, though the final version changed little in concept. The Nintendo 64 version was to be more vague and left to the player's imagination through its sparse dialogue. Itoi attributed the change in tone to his own growth and the character composition of the new development team. He said that he had not been changed by fans. Itoi always planned for the two brothers to fight each other, though he did not write the ending until after production had already begun, a process he compared with Hayao Miyazaki's. Itoi processed each line individually as he wrote the final scene, and later reflected on its moral content that bad people sometimes need even more help than the good people. He said that the one line that makes him most emotional is, "You must be tired." Itoi felt that the ending's renewal theme reflected his worldview of appreciating our time on Earth in light of the planet's inevitable end. Much of the rest of the script was written after-hours at a local hotel where they would continue their work. The game was about 60 percent finished by July 2004 and was set for a late 2005 release in Japan.