Kazuki’s past is marked by tragedy and emotional trauma. Before becoming a hitman, he led a more ordinary life and was once married. However, his former life was shattered by a mission gone wrong, leading to the loss of his family and his retreat into the underworld. Wracked with guilt and longing for connection, Kazuki buried himself in his work until fate brought Miri into his life.

Though reluctant at first, Kazuki steps up to care for Miri after her biological mother proves unfit and her father ironically one of Kazuki’s targets is eliminated. With Rei as his reluctant co-parent, Kazuki begins building a home life for Miri, balancing assassinations with bedtime stories, school lunches, and emotional growth.

Kazuki is a tall, athletic man with messy blond hair, often tied back in a loose ponytail, and light-colored eyes. He dresses stylishly and casually, usually in modern streetwear that reflects his relaxed personality outside of missions. During hits, he opts for practical clothing that allows mobility and concealment.

His expressive face, frequent smirks, and playful demeanor contrast with the cold efficiency he displays on the job, making him both approachable and dangerous in equal measure.

Kazuki is charismatic, outgoing, and emotionally intelligent, often serving as the social bridge in both his professional and domestic life. He is flirtatious and humorous, frequently joking around or making light of stressful situations. However, beneath his cheerful persona lies a man burdened by guilt and longing for redemption.

Despite his line of work, Kazuki is deeply empathetic. He takes pride in cooking, cleaning, and caring for others a stark contrast to his profession as a killer. His nurturing instincts make him the natural caregiver in the household, and he quickly grows attached to Miri, finding in her a chance to make up for his past and discover a new sense of purpose.

• The Mission that Changed Everything
  Kazuki and Rei are hired to eliminate a criminal target, only to find the man’s daughter, Miri, unknowingly wandering into the crossfire. After the mission ends, Miri ends up in Kazuki’s care, believing him to be her father. What begins as a temporary arrangement turns into a long-term commitment, with Kazuki deciding to raise her despite the complications it brings to his lifestyle.

• A Hitman and a Father
  As Kazuki tries to maintain his hitman duties, he also becomes a full-time father preparing school lunches, attending events, and protecting Miri from the truth of his profession. His domestic skills and emotional availability allow him to adapt more naturally than Rei, though he often struggles with the contrast between the violence of his job and the innocence of his new daughter.

• Confronting the Past
  Throughout the series, Kazuki’s backstory is gradually revealed, including the loss of his former wife and unborn child. These memories fuel his desire to do right by Miri, even as he questions whether someone like him deserves a second chance at family. His arc is one of redemption, healing, and self-forgiveness.