<P> Upon his return to Earth a year later, Goku encounters a time traveler named Trunks, the future son of Bulma and Vegeta, who warns Goku that two Androids (人造 人間, Jinzōningen, lit . "Artificial Humans") will appear three years later, seeking revenge against Goku for destroying the Red Ribbon Army when he was a child . During this time, an evil life form called Cell emerges and after absorbing two of the Artificial Humans to achieve his "perfect form," holds his own fighting tournament to decide the fate of the Earth, called the "Cell Games". After Goku sacrifices his own life a second time, to no avail, Gohan avenges his father by defeating Cell after ascending to the second level of Super Saiyan . Seven years later Goku, who has been briefly revived for one day and meets his youngest son Goten, and his allies are drawn into a fight by the Supreme Kai against a magical being named Majin Buu . After numerous battles resulting in the destruction and recreation of the Earth, Goku (whose life is permanently restored by the Elder Supreme Kai) destroys Majin Buu with a "Spirit Bomb" attack containing the energy of everyone on Earth . Goku makes a wish for Buu to be reincarnated as a good person and ten years later, at another martial arts tournament, Goku meets Buu's human reincarnation, Uub . Leaving the match between them unfinished, Goku departs with Uub to train him to become Earth's new defender . </P> <P> Kazuhiko Torishima, Akira Toriyama's editor for Dr. Slump and the first half of Dragon Ball, felt that the Dragon Ball anime's ratings were gradually declining because it had the same producer that worked on Dr. Slump . Torishima said this producer had this "cute and funny" image connected to Toriyama's work and was missing the more serious tone in the newer series, and therefore asked the studio to change the producer . Impressed with their work on Saint Seiya, he asked its director Kōzō Morishita and writer Takao Koyama to help "reboot" Dragon Ball, which coincided with Goku growing up . The new producer explained that ending the first anime and creating a new one would result in more promotional money, and the result was the start of Dragon Ball Z . The title was suggested by Toriyama because Z is the last letter of the alphabet and he wanted to finish the series because he was running out of ideas for it . </P> <P> Dragon Ball Z is adapted from the final 325 chapters of the manga series which were published in Weekly Shōnen Jump from 1988 to 1995 . It premiered in Japan on Fuji Television on April 26, 1989, taking over its predecessor's time slot, and ran for 291 episodes until its conclusion on January 31, 1996 . Because Toriyama was writing the manga during the production of the anime, Dragon Ball Z added original material not adapted from the manga, including lengthening scenes or adding new ones, and adding new attacks and characters not present in the manga . For example, Toriyama was asked to create an additional character for Goku's training with King Kai, resulting in the cricket Gregory . </P> <P> Throughout the production, the voice actors were tasked with playing different characters and performing their lines on cue, switching between roles as necessary . The voice actors were unable to record the lines separately because of the close dialogue timing . When asked if juggling the different voices of Goku, Gohan and Goten was difficult, Masako Nozawa said that it was not, and that she was able to switch roles simply upon seeing the character's picture . She did admit that when they were producing two films a year and television specials in addition to the regular series, there were times when they had only line art to look at while recording, which made giving finer nuanced details in her performance difficult . </P>

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