The mentor for the Quinx squad that is established to surpass the CCG's strongest Special Class Investigator Arima Kisho. Although being pushed around often, he tries his best to live with and guide the members of the squad. With a gentle personality and strong sense of responsibility, he connects with people easily. He has lost the memories of the last 20 years, and he looks up to his superiors, Mado Akira and Arima Kisho, as his parents.

Leader of the Quinx Squad. An honor student who skipped grades at the Academy. He has sharp observation skills and an excellent sense of combat. He doesn't like to cooperate, prefers to work alone and looks down on the other squad members. He is poor at showing emotions, but his jealousy is stronger than anyone else. His father was a former Special Class Investigator, who died fighting the One-Eyed Owl. To exact revenge, he is obsessed over being promoted into the S3 Squad that his father led.

A boy who has shark-like teeth. For some reason, he is obsessed with money and agreed to become a Quinx for monetary rewards. He has a simple and straightforward personality, and an unexpectedly strong sense of responsibility when it comes to important assignments. Despite his delinquent-like appearance and crude words, he cares a lot for his comrades. He often has disagreements with Urie, who is a total opposite of him.

An investigator who calls Haise "Teacher". Both of his parents were killed by Ghouls, and he was taken into custody by the Academy. He is serious but shy and is bad at dealing with blood. He is diligent with investigations, but with no avail. After the Quinx surgery, he did not show any significant growth in his strength and ability, as compared to the other members. Due to the surgery, he hides his left eye behind an eyepatch. Amongst the members, he has least Rc count, which is a type of cell found in Ghouls. As such, he is unable to summon his kagune.

A NEET inspector who’s a shut-in, living comfortably in her own room. Although with the highest aptitude and the best candidate for a Quinx amongst the squad, she is not motivated at work since she had never intended to become an inspector in the first place. She is terrible at time management and even Urie has given up on making her participate in investigations. Her hobbies are watching anime, playing games, reading manga and collecting figures. She is conscious about her chubbiness.