The Illusion of Safety: As a child, Do-young watched a young, charismatic Ki-hyeon on television, forming an idealized fantasy of him. When they reunite in high school, she is timid and harbors a deep, unrequited love.The Pawn and the Breaking Point: Because of her profound devotion, she allows herself to become a pawn for Ki-hyeon. She endures intense emotional manipulation and public humiliation just to stay close to him. After reaching her final breaking point, she painfully chooses to completely sever her feelings.The Adult Transformation: Nine years later, the modern arc reveals a drastically transformed Do-young. Shedding her past timidity, she sports a bold "baddie" persona complete with tattoos and piercings. As Ki-hyeon's workplace mentor, she remains completely cold, detached, and strictly professional, demanding he keep their high school past an absolute secret.

Initially appears gentle and innocent, but possesses a cold, calculating, and psychologically complex/yandere personality.Shaped by a chaotic childhood and a terrible relationship with his parents.His heart initially belongs to his childhood friend, Kim Ga-on, and he treats Do-young with cold detachment or irritation before deeper, darker obsessions and jealousies start to spark. A Fractured Childhood: Ki-hyeon’s outward presentation as a gentle, flawless student is entirely artificial. His private childhood was defined by immense trauma, including his father’s relentless infidelity and his mother’s subsequent suicide. Because public attention felt like threatening exposure rather than warmth, he grew up emotionally detached, sharp, and highly calculating.High School Cruelty & Latent Conflict: In their youth, he despised Do-young's unconditional affection, misfiling it as shallow. He aggressively used her one-sided love to try and provoke his true fixation, Ga-on. However, deep down, he harbored a confusing physical and emotional pull to Do-young—a conflict that made him feel so guilty that he lashed out at her with extreme verbal cruelty to deny it.The Tables Turn: As an adult, Ki-hyeon finds himself entirely reversed—he is now the one pathetically and desperately yearning for Do-young. Forced to work beneath her, he struggles desperately with intense jealousy and panic as she treats him like a total stranger, particularly as his toxic father resurfaces in his life to leech off his inheritance.

Seo Ki-hyeon’s childhood friend who holds a primary place in his heart early on and acts as a catalyst for his complex emotional fires. The Original Anchor: Ga-on is Ki-hyeon’s childhood friend and the absolute center of his universe during high school. Because she was his only source of emotional safety during his family’s collapse, his attachment to her bordered on an intense, desperate fixation.The Catalyst: In the prologue, she unwittingly drives the plot forward; Ki-hyeon's entire manipulation of Do-young's feelings was a calculated ploy to win over or elicit jealousy from Ga-on. Do-young also briefly dates or links closely with Ga-on in the past. As the adult arc progresses, Ga-on takes a major step back from the spotlight, leaving the unresolved damage between the two leads to fester.