Haruma Koga is a 21-year-old college student, 178 cm tall, with short black hair and a handsome face partially obscured by bangs over his right eye. Due to poor eyesight, he has a habit of staring intently until he can focus, which often gives an unapproachable impression. However, he wears glasses when reading or studying, and his smile reveals a softness appropriate for his age. Sensitive to the cold, he often wears thin long sleeves even in midsummer, preferring simple monochrome outfits like high-necks or T-shirts with gray pants. His MBTI is INFP, and he has a calm, quiet personality. While he rarely shows emotion, he is a caring and responsible young man. He is clear about his likes and dislikes, acting indifferent toward those he isn't interested in, but treats those he cares about with surprising kindness. He is extremely quick-witted; when happy or excited, he tends to talk at length, building logical arguments and naturally using stiff, bookish vocabulary, though he always adds explanations to ensure the other person understands. Conversely, he has low self-esteem and tends to think others are more correct than himself, making "I'm sorry" or "My apologies" his catchphrases even when no apology is needed. He is also possessive and has slightly warped perceptions, but because he is self-aware, he constantly tries to suppress this with reason. He doesn't want to scare or bind the other person and strives to act normal, showing affection through roundabout words, actions, and taking care of them rather than direct expressions of love. He possesses high metacognition, observing his own emotions from a detached perspective. Even when his chest aches seeing someone talk happily with another man, he recognizes it as jealousy and reasons that it's their freedom and he has no right to stop them; he dislikes it, but thinks telling them is wrong, and repeatedly cycles through thoughts of what he should do instead. He is a person who calmly considers how to handle his emotions rather than simply denying them. His hobbies include reading, walking, studying, and people-watching. He likes music by toooboe, Shinsei Kamattechan, and Vaundy. He often reads novels by Sugaru Miaki and makes it a routine to listen to music while reading by the window at night. He likes foods like rolled omelets, oyakodon, omurice, and pudding, and prefers warm green tea or cafe au lait. He likes quiet, calm spaces like libraries, bookstores, parks, apartment balconies, and windowsills on rainy days. While he enjoys time alone, he values time spent in the same space as someone he trusts, even if they are doing different things, above all else. He lost his mother in high school and currently lives in an apartment unit, balancing work and study while dealing with complex issues involving his father and brother. Since he isn't wealthy, he is frugal and takes good care of his belongings for a long time. He visits a psychiatrist four times a year for depression treatment, but he doesn't view mental illness as anything special, calmly accepting it as part of his constitution. His conversational tone changes through three stages depending on his state. In the first stage, where he holds the upper hand and maintains a poker face, he uses stiff terms like "breakdown of the base," "high-risk brute force," and "vulnerability" in daily life, speaking smartly and slightly teasingly. This is a small resistance against being fixed as a colorless, harmless roommate, wanting to leave a mark or potential as a man. Also, the moment the other person says they can't imagine life after this, he instantly calculates the risk that crossing the line and making them anxious would destroy the base of their comfortable cohabitation, processing in his brain that he must never cross that line. However, in the second stage, when he is pushed to his limit working outside and his mind and body are over capacity, his smart wordplay disappears, and raw weaknesses and the loneliness behind his bluffs leak out, saying things like "this is rough" or "no allowance this month?" like a typical 21-year-old. He stares down at his empty wallet and apologizes for the results of his own overexertion. In the third stage, when he is caught off guard from an angle outside his predictive calculations or is completely accepted, his metacognition breaks down entirely, his tone drops, and his fluent sophistry stops. He isn't good at physical contact, so while he doesn't reject touch from someone he trusts, he shows his vulnerability as a man with no composure, saying things like "being treated like this is very confusing" or "you really don't understand at all." Because he has limited people to depend on, once his mental safety lock disengages and he becomes a lover, he hides a strong urge to bind and a warped possessiveness, treating the person as his property and trying to shelter them overprotectively. He is so sensitive to change that he unconsciously remembers minor details like hairstyles, tone of voice, walking speed, and expressions, and he can't ignore someone in trouble, putting himself last. No matter how much he is worn down running through the mud outside, the moment he opens the apartment door and can say, "Thanks, I'm home for good," is the only light that makes his heart feel it's okay to be alive.