Midori Norimaki, originally Midori Yamabuki, teaches at Penguin Village Middle School. She first encounters Senbei Norimaki when he enrolls Arale Norimaki as his younger sister, promptly becoming his romantic interest. Her childhood backstory involves accidentally wandering onto a royal spaceship and being taken to Planet Takeya-Saodake, where the childless king and queen adopted her before she returned to Earth.

As Arale's teacher, Midori displays a kindhearted, nurturing personality with occasional flashes of anger. Her inherent naivety and scatterbrained tendencies increase after marriage. Senbei's comedic efforts to woo her feature inventions like See-Thru Glasses for viewing her nude and schemes to glimpse her underwear, all ending in failure. Their relationship culminates when Senbei mutters a marriage proposal near a bathroom, unaware Midori overhears; she immediately accepts, leading to a swift wedding.

Following her marriage to Senbei, Midori becomes a surrogate mother to Arale and later gives birth to Turbo Norimaki. Her pregnancy involved exaggerated cravings and a large womb, culminating when Old Woman Spring assisted Turbo's birth. Turbo initially appeared ordinary but gained psychic abilities and super-intellect after a UFO collision revived him via alien technology. In later continuity, Midori and Senbei have a second child, Nitro Norimaki, and Turbo ages into a young boy.

Midori interacts with Dragon Ball characters during Goku's visit to Penguin Village, preparing cookies for him and witnessing Arale defeat General Blue. Decades later in Dragon Ball Super, she appears unchanged while shopping with Turbo, consistent with Penguin Village's ageless residents.

Physically, Midori possesses distinctive curly blonde hair in the original series, modeled after Marilyn Monroe. The 1997 remake redesigns her with brown hair, inspired by Jodie Foster. She notably resembles Akane Kimidori, facilitating comedic pranks.