Arale Norimaki is the central character of the Dr. Slump series, created by the inventor Senbei Norimaki. She is a humanoid robot designed to look like a young girl, and her creation marks the beginning of the story's adventures in the quirky Penguin Village. While she is a highly advanced piece of technology, she is known for her childlike innocence, incredible energy, and a profound lack of common sense, which often leads to chaotic and humorous situations.

Her background is deeply tied to her inventor. Senbei built her in his laboratory, and to help her fit into the community, he presents her to the public as either his younger sister or his daughter. Despite his attempts to pass her off as a normal human, her extraordinary abilities make this a constant, amusing challenge. A notable physical trait is her nearsightedness, which requires her to wear a pair of large, round glasses. This feature was originally a simple gag, but creator Akira Toriyama kept it after readers expressed how it made them feel better about wearing their own glasses.

Personality-wise, Arale is defined by a charming and often bewildering naivete. She approaches the world with boundless curiosity and a cheerful disposition, greeting people with her signature phrase "N'cha". Her understanding of social norms is practically non-existent, leading her to perform acts that are either bizarrely innocent or terrifyingly destructive without any malice. For example, she has a well-documented fascination with poking piles of feces with a stick, a running gag throughout the series. Her motivations are simple and childlike; she seeks fun, friendship, and new experiences, and she explores the dynamics of life in Penguin Village with an unfiltered and joyful perspective.

As the protagonist, Arale is the engine of the series' humor. As a gag manga with no overarching plot, each chapter or episode revolves around her interactions with the eccentric residents of Penguin Village and the strange adventures sparked by Senbei's inventions. Her role is to be a force of pure, unadulterated chaos that exposes the absurdity of everyday life. She treats threats, from schoolyard bullies to alien invaders, with the same casual indifference, usually dispatching them with a single, effortless strike.

Her key relationships define her world. Her most important bond is with her creator, Senbei Norimaki, who acts as her father figure. She is incredibly loyal to him, even as her actions routinely derail his schemes. She becomes a big sister when Senbei marries Midori Yamabuki and they have a son, Turbo. Another crucial companion is Gatchan, a small, winged, metal-eating creature that hatched from an egg Arale and Senbei brought back from the prehistoric past. Gatchan is often by her side, adding to the household's delightful chaos. She also has a circle of friends from school, including the tomboyish Akane Kimidori and the gentle Peasuke Soramame. Her long-term relationship is with Obotchaman, a sensitive robot created by Senbei's rival, Dr. Mashirito, who eventually becomes her husband.

Development in Dr. Slump is minimal by design, as the series prioritizes maintaining its comedic status quo. However, the world around Arale evolves. She goes from being a new "sister" in Senbei's household to a beloved member of a growing family that includes a stepmother, a younger brother, and eventually a husband. Physically, her design evolved over the course of the manga, becoming shorter and cuter, a change that was later explained in-universe as her having multiple backup bodies of different sizes. Her role expanded beyond her own series when she made crossover appearances in Akira Toriyama's more famous work, Dragon Ball. In these appearances, she famously defeats the villain General Blue with ease and is shown to be pure of heart by riding the Flying Nimbus cloud.

Notable abilities are where Arale truly defies all logic. Her primary power is superhuman strength of a completely absurd degree. She can casually chop the Earth in half with her "Chikyuwari" Earth Chop, shatter the moon by throwing a rock, or punch a villain so hard they fly around the world. She is also capable of firing a powerful energy beam from her hands known as the "N'cha Cannon". Beyond raw power, her robot body allows her to perform gags like detaching her head from her body and throwing it around, or reassembling herself after being blown apart. She is also highly intelligent in a factual sense, able to solve complex equations and perform surgery, but this knowledge rarely, if ever, helps her navigate social situations.