Shusei Kagari was designated a latent criminal at age five during a Ministry of Welfare medical exam, leading to immediate confinement in the Hachiouji Rehabilitation Center. His designation documented a zero percent rehabilitation possibility. Early in confinement, he formed a brief connection with another child, communicating via lip reading across cells; this friend died during an escape attempt. Kagari remained confined for 14 years until his August 2110 release. He joined the Ministry of Welfare Public Safety Bureau's Criminal Investigation Department, Division 1, as Enforcer Hound 4 in October 2110. He chose this role over permanent isolation, viewing it as societal sacrifice. Kagari displayed a casual demeanor masking underlying resentment toward the society that imprisoned him. He often teased colleagues lightheartedly and enjoyed portable video games, sweets, and cooking during downtime, specializing in medamayaki taco rice. Yet he harbored significant animosity toward the Sibyl System and his captors, expressing satisfaction upon their deaths. He remained apathetic toward citizen safety or Sibyl's destruction but despised those taking freedom for granted. Despite this, he demonstrated dedication to his duties and formed genuine bonds within Division 1. After an initial physical confrontation, he developed a friendship with Shinya Kogami and shared a sibling-like rapport with Yayoi Kunizuka. Physically, Kagari stood 165 cm tall with a slim build, spiky orange hair, and brown eyes. His hair was often partially secured by four teal barrettes arranged to resemble the Roman numeral XII. His typical attire was a black jacket with rolled sleeves, black shirt, red tie, and black pants featuring two thin white belts. During fieldwork, he wore a standard CID windbreaker. Kagari discovered the Sibyl System's true nature during an investigation into Shogo Makishima's activities within NONA Tower's underground. Witnessing its physical form triggered his immediate execution by Chief Kasei using a Dominator in Destroy Decomposer mode, eliminating him to conceal the System's secret. Officially, he was declared missing in February 2113 during an investigation into riots involving Psycho-Pass camouflaging helmets. His death remained concealed from most colleagues; Akane Tsunemori was the sole Division 1 member aware. His background was further detailed in the novel *Chaser Shusei Kagari*, exploring his youth in isolation and early Enforcer experiences pursuing Makishima's associates.