Yuki is Saji's busty childhood friend and somewhat an unintentional rival to Koizumi.
Yuki has grown well-proportioned and shapely. However, her charm and body, while still able to make guys drool, are not as effective as Koizumi grace and mystery. Throughout the series Yuki finds ways of putting her towering breasts on Keisuke's face. Towards the end of the series her nerves get the better of her and she repeatedly tries to seduce Keisuke, eventually succeeding with the help of her enormous breasts. Despite her appearance she has very low self-esteem because guys like the smaller more, petite Koizumi and the fact that her old boyfriend, who was the captain of the basketball team, broke up with her because she was better than him.