Ayaka Usagida, often referred to as Ayaka-chan, is the protagonist of the story, a young office worker who finds herself deeply and unmistakably in love with her senior colleague, Hiroko Kano. Her background is that of a diligent and previously quite serious employee, known for her stone-faced demeanor at work before her feelings for Hiroko began to change her. This initial seriousness gave way to a more expressive personality as she started to alter her appearance and dress style specifically to capture Hiroko's attention.

In terms of personality, Ayaka is defined by her passionate and determined nature. She does not shy away from her emotions and pursues her romantic interest with a bold and sometimes reckless honesty. Unlike her more reserved senior, Ayaka is emotionally transparent and unafraid to express what she feels, freely making her affections known despite a lack of reciprocation. This persistence is a core part of her character; she refuses to give up even when her advances are consistently misinterpreted or politely deflected. While she is often the instigator of the story's romantic comedy elements, her straightforwardness is paired with genuine vulnerability, leading to moments of frustration and worry when her feelings are not understood.

Her primary motivation is singular and clear: to win the heart of Hiroko Kano and build a genuine romantic relationship with her. This drive fuels her actions both in and out of the workplace. After she and Hiroko finally begin dating and start living together, her motivation evolves but remains focused on deepening their bond. She becomes concerned about the dynamics of their new relationship, particularly when she perceives a lack of initiative from Hiroko, leading her to seek advice and try new approaches to bridge the gap between them.

Within the story, Ayaka serves as the narrative's emotional engine. Her relentless pursuit of Hiroko and her subsequent navigation of their official relationship create the central plot and much of the comedy, which often stems from a series of misunderstandings between the two lovers. Her role is not just that of a lovestruck junior, but also as a catalyst for other characters, such as her coworker Risa, whose own feelings are awakened by watching Ayaka's passionate chase.

Ayaka's key relationships are central to her development. Her bond with Hiroko is the focal point of her life, a relationship that progresses from one-sided admiration to a live-in partnership that requires communication and compromise. She also shares a significant friendship with her coworker Risa Komai, whom she trusts and turns to for advice on her romantic troubles, unaware at first of Risa's growing romantic feelings for her. Other colleagues, such as the supportive senior Yumi Kameda, also play a part in her work life and romantic journey.

Throughout the narrative, Ayaka exhibits notable personal growth. She evolves from a serious and somewhat reserved individual into someone who is more open with her emotions, a change that inspires those around her. By the time of the second stage of the story, which takes place after she and Hiroko have started living together, her character is described as having become even more well-rounded and full of humanity, developing a nurturing and almost maternal side in her affection for Hiroko. She learns to navigate the complexities of a committed relationship, moving beyond the initial chase to focus on building a stable and genuine partnership. Her abilities lie not in any special skill, but in her emotional resilience and her capacity for unwavering love and persistence, which ultimately drive the story forward and help break through the walls her partner has built.