; : : : Kyū is a bright, optimistic, and highly skilled detective who serves as the leader of Class Q. Known for his logical reasoning and sharp judgment, he openly supports Ryū when others distrust him. He harbors affection for Meg, often teasing her while deeply caring for her. Raised as an only child by his mother, Kyū was unaware that his mentor during childhood was actually his father, Satoru Renjō—Morihiko Dan's partner and right-hand man. Renjō had secretly married Kyū's mother to protect them from the dangers of his profession. After rescuing Kyū from a kidnapping at age five, Renjō later died, prompting Kyū's mother to conceal the truth for years. Once Kyū joined the DDS, she ultimately chose to support his pursuit of detective work. ; : : : Ryū is the grandson of King Hades, founder of Pluto, who sent him to DDS after his parents' death. Raised by Pluto, he bears the organization's mark on his neck. Isolated in his youth, he saw his home as a prison, shaping his reserved demeanor. Despite his cold exterior, he bonds with Class Q, particularly Kyū, the first to truly understand him. Though more naturally skilled, Ryū acknowledges Kyū's superior detective abilities, attributing them to his persistence and dedication. Ryū suffers from amnesia regarding his childhood, a condition later revealed to be induced by hypnosis. Kyū uncovers his Pluto connection but keeps it secret while aiding his search for the truth. After the hypnosis is lifted, King Hades removes the final mental block, deeming his plan a failure. Ryū then recalls his father's survival and reunites with him. ; : : : Meg, commonly known as , is a member of Class Q with an
eidetic memory, enabling her to instantly memorize scenes and detect altered evidence. She harbors romantic feelings for both Kyū and Ryū, though Ryū remains indifferent while Kyū teasingly reciprocates. She previously studied at the Tokyo National Talent Development Research Center alongside Yutaka Saburōmaru and currently lives with her university-student sister, Akane, as her parents work abroad. Upon first meeting Ryū, Meg senses familiarity despite being unable to recall him—an anomaly given her photographic memory. After recovering suppressed memories, she remembers they both attended the Tokyo National Talent Development Research Center. ; : : : Kazuma is a renowned computer game programmer who assists Class Q with his ever-present laptop. Initially dissatisfied with Class Q's perceived inferior status, he attempts to transfer to Class A but chooses to remain after his classmates support him during a crisis. He maintains a friendly rivalry with Kinta, frequently exchanging jokes while differing in investigative methods. Though a prodigy, Kazuma initially relies on his "lucky" hat for correct deductions but eventually overcomes this dependence. ; : : : Commonly known as , he is the son of a prominent police officer but lives independently after a family dispute, working various part-time jobs. As Class Q's strongest member, he trains in judo, kendo, and karate, possessing exceptional eyesight and olfactory senses. Kinta frequently ridicules Kazuma's technological methods, favoring instinctual detective work instead. His physical prowess and acute senses prove valuable during investigations. ; : : : Dan is the founder and principal of DDS, a renowned detective licensed as Japan's only private investigator permitted to carry firearms. A former police officer, he established Dan Detective Company (DDC) and its subsidiary DDS, developing both into elite institutions with the help of his protégé Satoru Renjō. Their most formidable adversary, the criminal organization Pluto, was seemingly destroyed at great cost—Renjō perished and Dan was left permanently unable to walk. When signs emerge of Pluto's resurgence, the aging Dan creates Class Q, selecting exceptional students to train as potential successors. He intends to evaluate their abilities and appoint his replacement from among them. ; : : : The loyal assistant of Dan, she assisted Meg, Kyū and Kinta in getting admitted to DDS, having met them during a case. ; : : :DDS's head of forensics, Maki is both a skilled teacher and doctor, and is quite intelligent in his knowledge of medical and forensic science. ; : : :Nanami serves as Dan's trusted assistant, specializing in disguise. He frequently monitors Class Q by posing as suspects during investigations. Though typically carefree—often demonstrating new disguises, including his signature cactus costume with a
sombrero—he becomes serious when required. Dan primarily assigns him to protect Class Q during Pluto-related cases. ; : : : Saburōmaru is an arrogant
Tokyo University student who enjoys boasting about his "superiority". He thinks that he will be a qualified detective. Although he has an
IQ of 180, he seems too inept in solving mysteries. Saburōmaru is initially in Class A after joining DDS, but later gets demoted to Class B. He knows Meg via the Tokyo National Talent Development Research Center and has a crush on her older sister Akane. ; : : King Hades, born , is Pluto's founder and Ryū's grandfather. The illegitimate son of artist Takumi Kuzuryū and criminal Yurika Kokuō, he retaliated against childhood bullies with an arson disguised as an accident. After rejecting Dan's friendship, he was imprisoned by Takumi in the "House of Dragon" basement, where he scarred his face and kept a blood diary before escaping and killing his father. As Pluto's leader, he attempts to groom Ryū through manufactured despair, but ultimately dies in a fire when his plan fails. ==Media==