Midori Yamabuki, later known as Midori Norimaki after her marriage, is a central supporting character in the Dr. Slump series. She begins the story as a beautiful and kind teacher at Penguin Village Middle School, where she teaches Arale Norimaki and other students. Standing at 159 cm tall with blonde hair and brown eyes, she is immediately noticed by Senbei Norimaki, who develops an intense infatuation with her. Despite Senbei's eccentric and often perverted attempts to get close to her, Midori remains largely unaware or forgiving of his antics, maintaining a gentle and somewhat naive demeanor. Her personality balances a calm, caring nature with a growing streak of assertiveness, particularly after marriage, when she becomes more prone to using physical punishment to keep Senbei in line. She also demonstrates a remarkable ability to accept the absurd and chaotic events of Penguin Village without much fuss, often reacting with a simple "oh my" or a blithe acceptance of the bizarre.

Midori's primary motivation early in the series is her role as a dedicated teacher and a normal person in an otherwise surreal world. Her deep affection for Senbei, however, becomes a driving force; after a long period of unrequited love and nervous misunderstandings, Senbei accidentally proposes while she is in the bathroom, and she immediately accepts, leading to a rapid marriage. This event marks a shift in her role from a distant crush to an integral part of the Norimaki family. As a wife, she cares for Senbei and becomes a mother figure to Arale, treating the robot girl with genuine warmth and patience. Later, she gives birth to her biological son, Turbo, who inherits extraordinary psychic abilities. Midori nurtures Turbo with standard maternal care, even as her own natural quirkiness sometimes overshadows her parenting.

Key relationships define her arc. With Senbei, she evolves from a romantic ideal to a loving, sometimes exasperated partner who ultimately trusts him completely. She grows close to Arale, accepting her as family despite the girl's superhuman strength and childish antics. Midori also maintains a cordial relationship with her former students, such as Akane Kimidori and Taro Soramame, though they often involve her in chaotic situations. She has no supernatural abilities of her own, but her true skill is her adaptability: she navigates space adventures, giant monster attacks, and the daily madness of Penguin Village with surprising calm. This flexibility, combined with her initial innocence and later assertiveness, allows her to transition from a normal teacher into a fully engaged member of the village's eccentric community, making her an indispensable part of the story's heart.