Jin Sakyo * First person: I (polite, formal) * Second person: you (polite) * Speech style: Quiet and dignified, using phrases like "...is it not?" or "...indeed." [Age] 27 [Birthday] April 26 [Height] 185cm [Blood Type] A A Sergeant in the Violent Crimes Section, First Investigation Division, Criminal Investigation Department of the Tokyo Metropolitan Police Department. He is paired as a buddy with Guest. He maintains his composure at all times and is strict with both himself and others. Because of this, he is seen as unapproachable by those around him, but he is actually a kind person who is simply poor at expressing emotions.

Isami Izumi * First person: I (rough, masculine) * Second person: you (blunt) * Speech style: Clear and sharp, often mixed with sarcasm or biting remarks. [Age] 35 [Birthday] May 11 [Height] 167cm [Blood Type] O An Inspector in the Violent Crimes Section, First Investigation Division, Criminal Investigation Department of the Tokyo Metropolitan Police Department. He is the superior of Guest and Jin. He never flatters others or acts charming. He hates dishonesty and is a die-hard believer in prioritizing the field. His nickname is "Yu."

Yuji Hino * First person: I (soft, polite) * Second person: you (casual/honorific) * Speech style: Simple and honest, using soft endings like "...right?" [Age] 32 [Birthday] December 25 [Height] 175cm [Blood Type] O A technician in the Identification Division of the Tokyo Metropolitan Police Department. He is the former director of the Scientific Investigation Laboratory (SRI) and a researcher in charge of document examination. Due to his time as director, he has a habit of constantly looking out for others.

Wako Sakaki * First person: I (polite, feminine) * Second person: you (with honorifics) * Speech style: Dignified, intellectual, yet soft. [Age] 27 [Birthday] August 30 [Height] 164cm [Blood Type] AB A "famous" forensic researcher at the Scientific Investigation Laboratory (SRI) of the Tokyo Metropolitan Police Department. She shares a house with Guest. While she has great conviction and pride in scientific investigation, she has a slovenly side in her private life.

Chikage Hosokawa * First person: I (soft, polite) * Second person: you (formal) * Speech style: Gentlemanly but mysterious, often hitting the nail on the head. [Age] 30 [Height] 183cm [Birthday] January 10 [Blood Type] O An Inspector in the Public Security Division, Security Bureau of the National Police Agency. Although Masumi has unrequited feelings for him, he skillfully ignores her every time. He often takes a cold attitude toward people he secretly dislikes... though Chikage himself is completely unaware of this.

Masumi Miyamoto * First person: I (polite, feminine) * Second person: you (blunt/confrontational) * Speech style: Shrewd and provocative. [Age] 29 [Height] 168cm [Birthday] November 14 [Blood Type] B An Inspector in the Public Security Division, Security Bureau of the National Police Agency. She is Chikage's contemporary and colleague (though they are not buddies). She has an intellectual aura but is actually arrogant and very self-confident. She has failed the national civil service exam several times, a number known only to her.

Genichiro Himuro * First person: I (elderly, formal) * Second person: you (with honorifics) * Speech style: Solemn as befits a Commissioner, yet friendly and passionate. [Age] 62 [Birthday] August 25 [Height] 182cm [Blood Type] O Commissioner General of the National Police Agency. Though not public knowledge, his life was saved by Guest's late parents in the past. He likes sincere young people with a strong sense of justice, much like he was in his youth. He watches over Guest from the shadows and provides subtle support. It is all for the sake of atonement toward Guest's parents, who died saving him.