Nontan is a white kitten distinguished by a pink nose and pink inner ears. His personality blends mischief and playfulness, driving him to explore and learn about his surroundings. Curiosity fuels his adventures, while occasional relatable flaws or "bad traits" enhance his appeal for young audiences, fostering identification.

Originally developed as a fox named "Akanbe Kitsune," then redesigned as a cat called "Akanbe Dora-kun," the character ultimately became "Nontan" for easy child pronunciation, inspired by the creator’s daughter. He inhabits a house marked by a rooftop flag. Initially living alone, Nontan is later joined by his sister Tartan, recognized by her blue ribbon and shared mischievous streak. Tartan’s name originates from the creator’s son’s sister. Nontan’s age varies across stories but is specified as four in "Nontan no Tanjōbi."

His social circle includes consistent friends and rivals. Buta-san, an apple-loving piglet, serves as a rival. Companions feature a trio of six-year-old pink rabbits—one boy and two girls—differentiated only by subtle ear variations. Other friends are Tanuki-san, a three-year-old tanuki who gazes at the sky and sings despite being tone-deaf; Kuma-san, an eight-year-old bear who leads the group and enjoys books, naps, and fishing; and Hachi-san, a communicative but non-verbal bee. Dr. Bear provides medical assistance. These interactions underscore themes of friendship, learning, and imaginative play.

Across media adaptations, Nontan retains core traits. In the CGI series, he hosts educational segments covering hiragana, katakana, numbers, shapes, colors, and health practices. Stories incorporate imaginative scenarios, such as encountering animal-specific Santas during Christmas Eve adventures, reflecting cultural narratives. Challenges like searching for a cat-specific Santa demonstrate his persistence alongside playfulness. Adaptations consistently reinforce his role in promoting curiosity, teamwork, and everyday learning through relatable experiences.