Rei comes from a strict and violent upbringing, raised by a powerful and abusive father who was also deeply entrenched in the criminal underworld. Groomed to be a killer from a young age, Rei’s life lacked emotional support, affection, or freedom. His stoicism and combat prowess are direct results of this harsh training, leaving him emotionally stunted and emotionally disconnected.

Eventually breaking away from his father’s influence, Rei joined forces with Kazuki, forming a hitman duo that blends Kazuki’s charisma with Rei’s lethality. Despite living independently, Rei continues to struggle with trauma, emotional detachment, and finding a purpose outside of killing until Miri enters their lives and starts to thaw his frozen heart.

Rei is tall and lean, with pale skin, long, straight black hair usually tied in a low ponytail, and icy blue eyes that reflect his distant, detached demeanor. His posture is often slouched or relaxed, giving off an air of indifference, but he moves with deadly efficiency when on a mission.

He typically dresses in casual clothing hoodies, sweats, or loose shirts and shows little interest in fashion or formality. His casual style and frequent blank expressions contrast sharply with the precision and brutality he exhibits in the field.

Rei is a quiet, introverted, and emotionally reserved individual. He prefers solitude, avoids unnecessary conversation, and finds comfort in repetitive or passive activities primarily video games and lounging around. His apathy is a shield developed from years of emotional suppression under his father’s control.

Though he rarely expresses emotion, Rei is deeply observant and highly intelligent, with a dry sense of humor that occasionally surfaces in unexpected moments. He struggles to express affection or vulnerability, but his actions often speak louder than words especially when it comes to protecting those he cares about.

As the series progresses, Rei undergoes significant emotional development, learning to open his heart to Miri, embrace responsibility, and redefine what it means to live on his own terms rather than in the shadow of his past.

• A Lethal Partner
  Rei operates alongside Kazuki as a hitman, acting as the team’s primary shooter and combat expert. He is rarely involved in planning or social interactions, preferring to follow Kazuki’s lead and keep to himself when not working. His professional efficiency and cold demeanor often intimidate others, but Kazuki understands and respects his quiet nature.

• The Reluctant Father
  When Miri Unasaka becomes a part of their lives, Rei is the most resistant to taking her in. He views her as a disruption to his simple routine and tries to maintain emotional distance. However, through small, meaningful interactions such as playing with her, sharing meals, or silently protecting her Rei slowly begins to bond with Miri in his own quiet way. Over time, he begins to change his behavior waking up earlier, helping around the house, and even adjusting his gaming schedule to spend time with her. These subtle shifts reflect his growing emotional investment and his desire to become someone Miri can rely on.

• Confronting His Past
  Rei’s greatest internal struggle is with his controlling father, who disapproves of his current life and urges him to return to the criminal organization. Their confrontation becomes a major turning point in the story, forcing Rei to choose between the life he was forced into and the life he’s slowly building with Kazuki and Miri. Ultimately, Rei rejects his father’s legacy, choosing found family and freedom over blood ties and duty an act that symbolizes his personal growth and emotional liberation.