Hana Matsuzaka is a high school girl and a classmate of the protagonist, Mayu Morita. She is distinguished by her curly blonde hair, a physical trait that makes her feel self-conscious to the point that she immediately apologizes whenever someone accidentally gets their fingers tangled in it. Initially, Hana finds Mayu difficult to approach because of Mayu's habit of staring very directly, which Hana interprets as an intense and even soulless gaze. Her natural shyness and tendency to overthink social situations make this first impression a significant barrier to forming a friendship.

Despite her quiet and timid demeanor, Hana's character is complicated by a difficult home life. There are ongoing domestic conflicts, particularly between her mother and grandmother, which create a tense and unstable living environment. This background gives Hana a hidden but distinct darker side. When she is reminded of her family struggles, her usual meekness can give way to expressions of genuine frustration and sadness, and she is capable of becoming surprisingly intense or gloomy. She is self-aware enough to openly acknowledge the parallels between her reality and her classmates' jokes about broken families, revealing a level of honesty about her pain.

Within the story, Hana is a member of the main friend group, which includes the talkative Miki Murakoshi and the more normal Chihiro Miura. Her role often revolves around navigating her own anxieties and misunderstandings with Mayu, but she is a regular participant in their shared school life, joining in on group activities, festivals, and casual outings. Her development is centered on overcoming her initial wariness of Mayu. A key moment occurs when Mayu straightens Hana's curly hair, an act of kindness that helps Hana feel more comfortable and allows her to warm up to her quiet classmate. Through these small interactions, she gradually builds a closer relationship with Mayu and the others, learning to see past the intimidating aura she first perceived.