Nao Koshiyasu (輿安 七帆), a supporting character introduced in the series' later seasons, attends the same school as the main cast. She interacts with protagonist Jin Kaito and his classmates, particularly those in school clubs. Affiliated with the photography club, Nao demonstrates an interest in photography. She is often grouped with other students outside Monaka Yatogame's immediate circle, including transfer students and fellow club members. The series occasionally features her in scenarios exploring regional Nagoya culture alongside other supporting characters, though her personal involvement is less central than the main cast's. Her role remains peripheral across seasons, movies, or other media, appearing primarily in ensemble scenes or group activities without significant character development, personal backstory, or individual story arcs. Sources sometimes romanize her given name as "Nanaho."