Ryuunosuke is highly intelligent and pragmatic, with a sharp ability to analyze people and situations. However, his blunt and direct nature often leads him to speak without considering others’ feelings, which can unintentionally hurt those around him. Though he usually maintains a cold and distant demeanor, he occasionally shows a softer side when caught off guard.

A socially withdrawn individual, Ryuunosuke is reserved and prefers solitude, contributing to his enigmatic presence in the dorm. His reclusive habits and aversion to in-person communication stem from his past experiences particularly a falling out with classmates who rejected his critical comments during a group project. This event left him wary of forming friendships and contributed to his hikikomori lifestyle.

Despite his aloofness, he is emotionally honest in his own way and occasionally exhibits tsundere-like behavior, especially toward Rita Ainsworth, who openly shows interest in him. Though he seems to harbor feelings for her, he struggles to express them due to his gynophobia (fear of women), which further complicates their interactions.

Aside from his passion for programming and artificial intelligence, Ryuunosuke has a strong fondness for tomatoes, which he frequently eats and refers to as a “superfood,” often consuming them even in unusual settings like the classroom.

Ryuunosuke has long, straight black hair that reaches his waist, styled in a hime cut, along with dark reddish-maroon eyes. His facial features are delicate and feminine, to the extent that he is often mistaken for a girl. He typically wears his school uniform, though he occasionally appears in casual clothing.

Ryuunosuke is fully aware of his androgynous appearance and shows little concern about it. During the school’s cultural festival in their second year, he wears a maid outfit without protest, casually remarking, “It’s just a school festival, what are you making a fuss over?” In the visual novel adaptation, he is later forced to wear a nurse uniform, though he expresses more discomfort in that instance.

Rita Ainsworth
Ryuunosuke has a complicated relationship with Rita due to his gynophobia and her initial status as a freeloader at the dorm. While their interactions begin with friction, Rita gradually falls in love with him. Ryuunosuke often avoids her, even isolating himself in the bathroom to escape physical proximity, claiming sensitivity to her presence and physical appearance. Nevertheless, he listens to her seriously and slowly begins to tolerate her presence, eventually becoming comfortable enough to sit near her and even shake her hand.

Rita kisses Ryuunosuke on the cheek both of their first kiss and later on the lips, which causes him to faint. Despite his embarrassment, their bond deepens over time. Rita even returns to Japan to deliver a Valentine’s gift to him, showing her devotion. When she later moves into Sakura Dormitory, Ryuunosuke and Kanna oppose her stay, though Sorata’s deciding vote allows it. Rita attempts to help Ryuunosuke overcome his fear of women, but her efforts initially backfire. After high school, their relationship progresses, and they begin going on monthly dates. By their second year of university, they have shared several kisses. On Christmas Eve, Rita announces her decision to return to England to pursue her dreams and asks if she can continue hoping for Ryuunosuke to reciprocate her feelings. He remains silent, possibly out of fear of holding her back, subtly implying that he cares for her but is hesitant to interfere with her goals.

Maid
Maid is an advanced AI program developed by Ryuunosuke to reduce his need for human interaction. She resembles a former classmate of his and is designed in a chibi style. Over time, Maid evolves into a fully interactive assistant, helping manage his communications and daily tasks. Ryuunosuke has expressed a desire for Maid to become a real human one day, seeing her development as a symbol of the future of technology.

Sorata Kanda
Ryuunosuke maintains a cooperative and at times friendly relationship with Sorata. He offers Sorata advice and technical guidance, especially in game development, and the two often engage in humorous banter. Sorata, though occasionally annoyed by Ryuunosuke’s blunt observations, respects his skill and relies on his support. Sorata is the first person in the novels to uncover Ryuunosuke’s past, and the two eventually form a game development team together. After graduating, they share a studio, and later, they co-found a game company alongside Iori Himemiya.

Iori Himemiya
Iori joins Ryuunosuke and Sorata’s game development project in Volume 9. Initially skeptical of Iori’s capabilities, Ryuunosuke threatens to remove him from the team. However, Iori proves his worth by composing the music for their game, earning Ryuunosuke’s respect. After high school, Iori moves in with Sorata and Ryuunosuke as they continue working on game development together.

Maya Ikejiri
Maya was a classmate of Ryuunosuke during middle school and one of the original members of a failed game development project. She was among the last to distance herself from him, which contributed to his eventual social withdrawal. In the light novel, it is revealed that Maya was in love with Ryuunosuke, though it is unclear whether he reciprocated her feelings.