Hazuki Shimada, Minami Shimada's younger sister and a fifth-grade middle school student, radiates cheerful optimism, starkly contrasting her older sister’s quick-tempered nature. Her unwavering admiration for Akihisa Yoshii leads her to affectionately dub him “baka-onii-chan” — a playful twist on Minami’s blunt “baka” — reflecting her fondness for his kindness and her bold declarations of intent to marry him someday. Despite her candid pursuit of Akihisa, her infectious positivity and universally endearing demeanor prevent others from taking offense.

Hazuki sports vibrant green eyes and pink hair styled in ribbon-adorned twintails, though certain depictions portray her with red locks. Her youthful charm is accentuated by a signature outfit of dresses paired with tights. While primarily a supportive figure, her lighthearted antics often ease tensions among peers, subtly enriching group dynamics. Her presence amplifies both comedic and heartfelt moments within the core cast, particularly through her earnest devotion to Akihisa and her spirited dynamic with the more volatile Minami.