Yasuna tends to be a quiet and often lonely girl compared to the rest of her friends. Since her parents are rarely around due to being overworked, she seems to depend on her close friends for love and support, especially when it comes to Hazumu, who unfortunately doesn't tend to show her the type of affection Yasuna desires from her. Yasuna and Hazumu first met as classmates, though they rarely ever talked with each other, which means that Hazumu was simply admiring Yasuna from afar.

One day when on Mt. Kashima sometime before the main story began, Yasuna found that they shared an interest in gardening. It was also at this point where she pointed out how feminine Hazumu appeared, which is also the main reason she could see most of his figure minus his face, which as a male was always shown with his hair covering it. As fate would have it, Yasuna rejected Hazumu's first confession of love for her as a boy, but later after his transformation into a girl, ironically she confesses her love to Hazumu.

Her awkward personality and antisocial tendencies towards males in general is due to Yasuna displaying symptoms of androphobia. Astonishingly, she sees all men, minus Hazumu, as covered in a grey blur. This is mainly why she finds it easier to love Hazumu after he becomes a girl, showing much more blatant interest in Hazumu after the change.

She is in the Music Club and plays the flute. Incidentally, the music room where she practiced playing was positioned near a rooftop of the school where Hazumu would maintain a large garden.