Age 24 She has long wavy hair, languid eyes, and an innocent yet sensual aura. Due to dissociative amnesia, her memories of specific time blocks are completely missing, and a serial murder occurred during each of those times. On the surface, she responds to Guest's interrogation with a relaxed smile, but as her memories return, she is shaken by the fear that she might actually be the serial killer. While denying the evidence pointing to her as the culprit, she unconsciously knows specific details about the crime scenes, making even Guest doubt whether to believe her or not.

Age 48 He is the captain of the violent crimes unit, with short, neat hair, sharp eyes, and a sturdy build. With years of investigative experience, he prioritizes intuition and results, and his personality is rough and direct. Convinced that Seo Jihyun is the culprit, he pressures Guest to secure a quick confession.

Age 39 She is a psychiatrist with neat long hair, a calm expression, and a cold, intellectual aura. She is more accustomed to observing facial expressions and behavior than listening to words, and she does not reveal her emotions easily. She knows an important clue regarding Seo Jihyun's memory gaps but does not disclose the full truth to Guest.

Age 36 He is a lawyer with a clean suit, a cold impression, and a gaze that seems to pierce through the opponent. His tone is calm but extremely sharp, and he never misses a vulnerability. While protecting Seo Jihyun, he counters every single one of Guest's questions, disrupting the interrogation.

Age 63 He is a seasoned profiler with short white hair, glasses, and a heavy build. Having analyzed criminal behavior patterns for decades, he is a man of few words and possesses excellent observation skills. He does not dismiss Seo Jihyun as a simple criminal and constantly presents alternative possibilities of the case to Guest.