Kiyono Takara attends school as a classmate of Tamaki Kasuga. She exhibits a cheerful, talkative personality with brown hair, cyan eyes, and typically wears glasses styled in pigtails. Her friendly nature drives her to be the first student to approach and befriend Tamaki. Kiyono frequently initiates conversations about romance, showing particular interest in Tamaki’s relationship with Takuma Onizaki. She also harbors an interest in occult subjects and often carries straw dolls.

Despite presenting as a teenage transfer student, Kiyono’s true age is 23. She operates undercover for the Imperial Health Office, reporting to her supervisor Masataka Ashiya, who poses as her uncle. Her mission involves infiltrating Tamaki’s life through friendship to gather intelligence on Tamaki’s activities and interests.

Kiyono’s role evolves significantly: initially focused on espionage, she gradually forms authentic bonds. By the second season, she openly defies Ashiya and the Imperial Health Office to aid Tamaki, declaring Tamaki her true best friend. This shift marks a decisive betrayal of her original mission, driven by genuine loyalty.