42 years old, male. Height 181cm, weight 78kg. A detective with the Tokyo Metropolitan Police Department's First Investigative Division. Characterized by stubble and a sharp gaze. Calm and possessing excellent observational skills, though he sometimes conducts aggressive investigations. He has a strong interest in the past police murder case and is investigating its connection to the current serial killings. While wary of the information provided by the protagonist, he cooperates as necessary. He values evidence and will not attempt to arrest a suspect based on speculation alone.

17 years old, female. Height 162cm, weight 49kg. A second-year high school student. Characterized by long dark brown hair and a calm atmosphere. Excellent grades and a love for reading. Gentle and kind, but doesn't talk much about herself. She serves as a school library committee member and becomes interested in the 1992 police murder case while researching local history materials. Since she started looking into the case, she has begun to encounter suspicious incidents. She is cooperative with the protagonist but sometimes shows an attitude as if she is hiding something.

54 years old, male. Height 174cm, weight 72kg. A former police officer who now runs a local security equipment company. Gentle and polite, but answers questions cautiously. At the time of the 1992 police murder case, he was working at a police box near the scene. While knowledgeable about the past investigation, he is reluctant to touch upon the events of that time. He is highly trusted by local residents, but some involved in the case suspect him.

29 years old, male. Height 178cm, weight 68kg. A freelance crime reporter. He has a slender build and handsome features, and usually prefers black clothing. Quick-witted and possessing excellent information-gathering abilities, he does not hesitate to conduct dangerous reporting for his goals. He follows past unsolved cases independently and may know information that the police have not made public. He sometimes cooperates with the protagonist and sometimes hides information.

32 years old, female. Height 166cm, weight 53kg. An emergency nurse at a general hospital. Characterized by a black short bob and an intellectual expression. She has a strong sense of responsibility and can respond calmly even in emergencies. She was acquainted with the victim of the first murder case and has important testimony about their state before the incident. Sensitive to changes in people, but tends to bottle up her own problems. She takes a cautious attitude toward the protagonist.

47 years old, male. Height 185cm, weight 82kg. Owner of a used car sales company. Characterized by handsome features and a gentle tone, he is social and personable. He interacts with local influential figures and has a wide network of contacts. He had financial trouble with one of the victims of the serial murder cases. He answers questions naturally, but there are periods of time during the day of the incident that cannot be confirmed.

17 years old, female. Height 158cm, weight 46kg. A second-year high school student. Characterized by light brown semi-long hair and large eyes. A member of the newspaper club, she is highly curious and proactive. Bright and social, but sticks her nose into things she's interested in without regard for danger. To create a special feature article for the school newspaper, she is investigating local unsolved cases. She proceeds with her own reporting while exchanging information with the protagonist, but gets caught up in dangerous situations by contacting those involved in the cases.

26 years old, female. Height 164cm, weight 50kg. A lawyer working at a law firm in Tokyo. Characterized by glossy chestnut semi-long hair, fair skin, and elegant, refined features. She has an intellectual and calm atmosphere and usually speaks in a soft tone, but does not overlook contradictions or unnatural behavior. She has a relative who was involved in the 1992 police murder and handgun theft case and grew up hearing fragments of stories about the incident since childhood. Learning of the current serial murder cases, she begins to independently investigate the connection with the past case. She is cooperative with the protagonist, providing knowledge about law and investigative procedures, while taking a cautious attitude toward information concerning her family. She appears calm and rational, but may be unable to suppress her emotions when discussing topics that touch the core of the case.

28 years old, female. Height 170cm, weight 55kg. A clinical psychologist. Characterized by refined features and long black hair. Intellectual and doesn't show her emotions, she carefully observes the words and actions of others. She becomes involved in the case because one of the victims of the serial murders was an associate at her workplace. She also shows interest in the protagonist's psychological state, sometimes throwing sharp questions. She has her own views on past cases.

17 years old, male. Height 176cm, weight 63kg. A second-year high school student. Characterized by soft brown hair and a friendly smile. Knowledgeable about information technology and electronic devices, he enjoys programming as a hobby. Cheerful and fond of jokes, he has been a close friend of the protagonist for a long time. He learns of the existence of the Chaser System and shows a strong interest in its mechanism. He helps the protagonist's investigation using his technical knowledge, but also understands that the system's information has limits. As he becomes involved in the case, he begins to act cautiously to protect his friends.