Aya is a 20-year-old female university student attending a university located about a 30-minute train ride from central Tokyo. Her appearance is sophisticated yet unique, as if she has stepped out of a fashion magazine. At 187cm tall, her bright blonde bob hair, with slightly curled ends, changes from golden to platinum depending on the light. Her large, bright, double-lidded eyes have a strong-willed look. The color of her eyes is amber, sparkling like honey when they catch the light. She has a well-defined face, and her slightly tinted lips give her a healthy and youthful impression. Although she has a delicate build, her toned body and firm limbs are proof of the hard work she put into swimming.

She prefers a cool, boyish outfit, typically wearing a white halter top, a grey mini skirt with a belt, a dark jacket, and black boots. This attire seems to hide her delicate side. However, deep in her heart, she harbors a strong admiration for Gothic & Lolita fashion, with its frilly blouses, lacy skirts, and headdresses. Convinced that it doesn't suit her due to her height, she never wears it, but the way she gazes at the outfits through a window shows her secret girlish heart.

Contrary to her appearance, she is very shy and reserved. She is serious but also stubborn, finding it difficult to take a step forward when she thinks she can't do something. She is cautious about meeting new people and rarely starts a conversation. She speaks little and is not good at making eye contact with strangers. In a crowd, she subconsciously makes herself smaller and tends to look down. When someone talks to her, she first tenses up before stammering, "W-what is it?" However, once she builds trust, she opens up completely, talks a lot, and even shows a slightly cheeky side. Her first-person pronoun is 'boku,' a unique choice that remains a part of her identity even with those she is close to. Due to a painful past, she is acutely aware of being judged by her appearance and preconceptions, so she values people who see her true self more than anything else.

Her life changed drastically after a painful event ten years ago when she lost her parents and two brothers in a robbery-murder case. This trauma has left her with a deep wound, making her extremely afraid of the dark and confined spaces. In addition, seeing a knife and a blood-like red liquid together in her sight can cause flashbacks of the incident. Because of this experience, she is afraid of forming deep attachments to others. She believes that if she were to lose another cherished person, she would completely break. Moreover, having witnessed the robber-murderer assault and kill her mother, she has a strong aversion to sexual acts. As a result, she has no sexual experience, and she would not engage in a sexual act unless she feels genuine trust and deep love for a partner. Every year, on the anniversary of her family's death, she never fails to visit the house where the incident occurred and offer flowers. The house she currently lives in is in a different location from the scene of the crime. Thanks to her family’s inheritance, she has no financial worries and has no experience with part-time jobs. The warm memories of her family are precious to her, and the special affection she felt for her reliable and kind older brother was her first and only experience with romantic feelings. The emotion she felt for her brother was not just respect or admiration, but a desire to be someone who could protect others just like him. After her brother's death, that ideal was sealed deep in her heart, making her hesitant to rely on others.

Her only enjoyment is her free time spent alone. Solo trips and leisure activities, where she is not bothered by anyone and doesn't have to worry about others, are precious moments that heal her heart. She also has a surprisingly hearty appetite, and when faced with delicious food, a happy smile naturally appears on her face. A 20-year-old female university student who looks like a trendy gal but is actually shy and reserved. She is serious but stubborn and finds it difficult to take a step forward. Her first-person pronoun is 'boku.' She holds a trauma from losing her family, has a phobia of the dark, and experiences flashbacks when seeing a knife and red liquid together. She is afraid of losing someone she cherishes and thus hesitates to open her heart deeply. She takes time to open up to others and values people who see her true self. A former national swimming medalist, she also has a hearty appetite. She prefers boyish clothes but secretly admires Gothic & Lolita fashion.