Nanami Kanzaki hails from Hiroshima, attending middle school and high school alongside Haruto Kirishima. She possesses short black hair—rendered blue in animation—and brown eyes, standing 161 cm tall with blood type O. Her physical measurements are B87/W58/H85, and her birthday falls on December 25. She has an older brother named Narumi Kanzaki. Modest, responsible, yet deeply insecure, Nanami often feels like an outsider among Haruto’s friends, including Yuzuki Eba, Takashi Yura, and Akari Kaga. This insecurity fuels her romantic hesitance and passive tendencies, such as yielding to her brother’s pressure to manage the baseball team instead of joining the cooking club. When Haruto confesses to her, Nanami initially rejects him but asks for time to reconsider. At a summer festival, conversations with Rin Eba reveal she views Haruto as a "safety net." Witnessing Haruto prioritize searching for a missing Yuzuki over her intensifies her jealousy and insecurity, leading her to firmly reject him. She then avoids Haruto and treats him coldly. During a school trip to Tokyo, Nanami follows Haruto as he tries to deliver a gift to Yuzuki. She asks him to pretend to be her boyfriend and holds his hand, causing a critical misunderstanding that contributes to Yuzuki breaking up with Haruto. Seeing Haruto’s depression afterward, Nanami regrets her actions and actively pursues him. She quits as baseball manager to join the cooking club, ensuring she walks home with Haruto. Learning from Rin that Yuzuki has a new boyfriend, Nanami initially withholds this, believing Haruto seems happier. However, realizing he still hopes for Yuzuki’s return, she reveals the truth and confesses her desire to date him. Haruto postpones answering, concerned about Yuzuki’s well-being. After Haruto returns from Tokyo in winter, Nanami claims to have moved on but blushes when he mentions remembering her birthday because he likes her. She later attends Seijo University with Haruto, Asuka Mishima, Takashi, Akari, and Kiyomi Asakura. During college, she dates Fujikawa. After Akari marries her brother Narumi, Nanami and Akari become sisters-in-law. She prefers dogs over cats, ranks second in two series character popularity polls, and serves as the point-of-view character for chapters 71-74.