Yanna Sasatsu, identified in Japanese as Sasatsu Yanna with surname precedence, serves as a central figure across all seasons of the series. She consistently anchors the primary group alongside Monaka Yatogame, Kaito Jin, and Mai Tadakusa, retaining this core position through the fourth season. Her involvement centers on school photography club activities, where group interactions focus on uncovering and clarifying Nagoya's local culture and dialect for Tokyo-transplanted Kaito.