Arale Norimaki is an android crafted by Senbei Norimaki in his laboratory, designed as a perfect humanoid robot with a young girl's appearance. Her creation fulfilled Senbei's ambition to build the world's first flawless android, though she possesses severe nearsightedness requiring corrective glasses. To integrate her into society, Senbei presents her as his younger sister or daughter to Penguin Village residents, who accept this despite her frequent superhuman displays. Her stated age is 13, yet her youthful appearance and childlike behavior often contradict this. Over time, her visual design evolved to appear shorter and younger, later retconned as the use of multiple bodies in different sizes.

Arale exhibits a cheerful, energetic, and naive personality consistent with childhood, despite advanced intelligence enabling her to solve complex mathematical equations and perform intricate tasks like appendectomies on frogs. She remains optimistic, friendly, mischievous, and easily distracted. Her interests encompass Japanese superhero shows like Ultraman and Astro Boy, giant monster films, and the compulsion of poking feces with sticks. She frequently uses unique phrases: "N'cha" as a greeting, "Bye'cha" for goodbye, "Hoyoyo" to express bewilderment, and emits a "Kiiin" yell while running arms outstretched. A recurring gag involves her dissatisfaction with her flat chest and tendency to lift her shirt without regard for social norms. Despite her naivety, she demonstrates a pure heart, riding Son Goku's Flying Nimbus cloud and showing deep care for family, friends, and animals.

Her superhuman capabilities include immense strength, enabling feats like splitting the Earth in half with one punch (the "Earth-Splitter" or "Chikyūwari" technique), destroying the moon by throwing a rock, and executing a "Rocket Punch." She exhibits invulnerability to conventional harm, surviving gunfire to the face unscathed (though her glasses may break), and her endurance falters only due to low energy levels requiring refueling. In combat, she effortlessly defeats adversaries like Dragon Ball's General Blue.

Activated in Senbei's lab, she failed an eye test and was fitted with glasses. She enrolled at Penguin Village Middle School, astonishing classmates and faculty with intelligence and strength, and befriended Akane Kimidori, Taro Soramame, and Peasuke Soramame after demonstrating her power. Her adventures include freeing a captive bear and sacrificing her body to save its life, leading Senbei to build her a new body. She traveled through time using Senbei's "Mr. Time" machine, inadvertently transporting to different eras. During a prehistoric journey, she and Senbei obtained a mysterious egg that hatched into Gatchan, a winged creature adopted into the family.

In one incident, she was kidnapped by a bank robber but treated it as an Ultraman game, destroying his hideout and disarming him after Gatchan ate his gun. Later, the same robber took hostages at a barbershop; Arale's nonchalant power display—including throwing a rock that split the moon—prompted him to abandon crime. She encountered extraterrestrial threats like King Nikochan, whose ship Gatchan consumed after they destroyed Mars, and Dr. Mashirito, who lured her teacher Midori Yamabuki to space. During the Space Adventure, Arale joined Senbei and classmates to rescue Midori from Mashirito's trap, though her oblivious nature often sidelined her from the mission's urgency.

Her family expanded when Senbei married Midori, and they had a son named Turbo. Gatchan later split into two entities. She formed bonds with characters including her eventual husband Obotchaman.

Arale appears in Dragon Ball crossovers, aiding Son Goku against General Blue and making cameos in Dragon Ball Super, where her gag-based abilities humorously challenge the series' serious fighters, reinforcing her canonical presence in Akira Toriyama's interconnected universe.