Nitro Norimaki

The Dr. Slump manga series features an extensive cast of characters created by Akira Toriyama. It follows the humorous adventures of the little girl robot Arale Norimaki, her creator Senbei Norimaki and the other residents of the bizarre Penguin Village.

While many of the characters are humans, the cast also includes anthropomorphic animals and objects, robots, extraterrestrial lifeforms, and gods. Characters that are parodies of historical figures, fairy tales, popular Western movies, and real people that author Toriyama knows are also common. Many of these characters make a minor appearance in Toriyama's more well-known series, Dragon Ball.

Toriyama drew several short omake manga included in the Dr. Slump tankōban volumes that supposedly depict the actual events of how he came up with the characters, although, as they are often humorous, the level of truthfulness to them is uncertain. In one he claimed that when he told his editor, Kazuhiko Torishima, that he wanted to make a manga about a doctor, Torishima told him to add a robot. Toriyama originally wanted a very large robot, but as it would not fit in the panels, instead made it small. When Torishima rejected that idea, he made the robot a girl knowing Torishima would find her "cute". Another depicts him, having wanted to give the Norimakis a pet monster and having that rejected by his editor as it was not cute, coming up with the idea of Gatchan after his sister brought her child to see him. Toriyama stated that Torishima enjoys romance and that the relationships of Arale and Obotchaman, Akane and Tsukutsun, and Taro and Tsururin in Dr. Slump were all his ideas.

Toriyama's editor Torishima was the model for the evil character Dr. Mashirito. Torishima later explained that when Toriyama decided to have a "mad scientist" appear, he told him the character's initial design was "too weak" and to come up with someone "nasty" to have a big impact, and to imagine the person he hates the most in the world. Having not received the manuscript until just before the deadline, Torishima did not have any time to change it with Toriyama having given the character Torishima's face and changed the name to his with the syllables reversed. The editor hoped the character would be unpopular and therefore a one-off, but everyone loved it because Toriyama had previously written about his editor and the audience knew who it was based on.

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