Yukari Tsukino is a middle school sophomore at Sakashitamon Academy as well as a tenant at the girls' dormitory. She has what Hachibei considers "ideal breasts." The trait is revealed to be hereditary because her older sisters have the same breast shapes but are larger. Her mother, however, doesn't have them at all. Yukari is very bashful, partly because boys make fun of her breasts, which are bigger than her peers'.

She excelled at Kyūdō and is the district champion. She is secretly a part of an otaku dōjin circle. She likes Hachibei and confesses her feelings to him. Since he does not understand true love, he can only reply by explaining his love of parts. This greatly upset her until Tsubame helped her to understand Hachibei better. She also uses her large breasts to get Hachibei to notice her, though she is still less significant to him than Ayame Yatsuhashi.

She later discovered that Hachibei and Tenmaku began dating but still couldn't stop loving him. However, after setting up a date after they were the only two left in the house, she realized she could no longer stand that he loves just her breast and not her. Where she thrusts him to the ground and forces a kiss. Even though she hasn't given up on Hachibei she does show to have feelings for her classmate friend who loves her as much as Hachibei.

When she believed Sakurako broke up with him, instead of taking advantage of the situation she encourages him to do whatever he could to get back with her, despite the emotional pain it caused her. At the end she states that Sakurako can handle his love, and she will handle his parts love before hugging his head into her breasts.