Shinya Kogami began as an Inspector in the Public Safety Bureau's Criminal Investigation Department, assigned to Division 03 before transferring to Division 01. He forged close bonds with his Enforcers, especially Mitsuru Sasayama. The investigation into the Specimen Case, involving dismembered victims displayed like specimens, ended tragically when Sasayama was murdered identically. Discovering Sasayama's mutilated body inflicted severe trauma that spiked Kogami's crime coefficient. Refusing treatment, he became obsessed with solving the case, leading to his demotion to Enforcer status as his mental state deteriorated. Operating under Inspector Akane Tsunemori in Division 01, Kogami's detective abilities remained sharp, solving cases through unconventional and often risky methods. Though typically detached, he displayed a sense of humor, particularly teasing Tsunemori about the incident where she shot him with a Dominator. Their working relationship evolved into mutual respect and trust, influencing his perspective on justice. His growing disillusionment with the Sibyl System peaked when it blocked him from pursuing Sasayama's killer, Shogo Makishima. This drove Kogami to abandon his position, becoming a fugitive to hunt Makishima alone, fracturing his long friendship with Inspector Nobuchika Ginoza. After Makishima's death, Kogami left Japan, working as a mercenary in conflict zones like Shambala Float, aiding oppressed populations. By 2116, he operated in Southeast Asia and the Tibet-Himalaya region, adopting military attire and carrying conventional firearms. There, he encountered Tenzing Wangchuk, a young half-Japanese girl whose parents were killed by guerrillas. Seeking revenge, she prompted Kogami to mentor her while he cautioned against the self-destructive path of vengeance, reflecting on his own hunt for Makishima. Protecting refugees, he crossed paths with Frederica Hanashiro of Japan's Ministry of Foreign Affairs, who was assisting stranded citizens. Wounded in combat, Kogami was aided by a fellow mercenary, Garcia, who later revealed himself as an antagonist sabotaging peace talks. After Garcia critically injured Tenzing, Kogami intervened, killing Garcia under Hanashiro's condition that he return to Japan. Kogami rejoined law enforcement as a Special Investigator within the Ministry of Foreign Affairs' Suppressing Action Department. Though operating outside the Public Safety Bureau, he remained wary of the Sibyl System. His return facilitated reconciliation with Tsunemori, whom he visited while she was imprisoned. Despite differing organizational ties, they continued collaborating on cases, demonstrating a professional dynamic rooted in mutual trust. His relationship with Ginoza also stabilized, though the closeness of their former friendship remained uncertain. Throughout his journey, Kogami adhered to the motto "Be gentle to others, but strict with oneself." His experiences transformed him from an idealistic Inspector to a disillusioned fugitive, and ultimately into a figure seeking redemption through protecting others rather than pursuing vengeance.