Atsuko Ueno is the original creator of the manga and anime series Kotencotenco, a comedic fantasy work aimed at young children. The series, whose title is also romanized as Kotenkotenko, revolves around the protagonist Kotenco, a kind and obedient child who serves as a protector of the Angel Star for the Queen of Heavenly Lands. In times of crisis, Kotenco transforms into his mischievous and troublesome counterpart, Matenco, who can only revert to his original form with the use of the Angel Ring.

The Kotencotenco manga was published by Kodansha in the magazine Tanoshi Yōchien. The story follows Kotenco and his friends, Pick-chan and Nappa, as they work to stop antagonists such as the Baron, Urusainu, and Nekoumori from stealing heavenly stars for the Great Demon King Agu, who seeks to take over Heaven Kingdom.

The anime adaptation of Kotencotenco was produced by NAS and TV Tokyo and aired on the TV Tokyo network. The television series was directed by Susumu Kudo and produced by the studio IMOVE, also known as Eye move. It originally ran for 52 or 104 episodes from October 6, 2005, to September 28, 2006. In addition to her role as the original creator, Atsuko Ueno is also noted as a mangaka, the Japanese term for a comic artist or cartoonist.