Japan's governing entity in the 22nd century, the Sibyl System operates as a private organization managing law enforcement and societal order through constant biometric surveillance. Its core is a hive mind composed of the surgically excised brains of criminally asymptomatic individuals—those whose psychological states evade its cymatic scanning technology. Membership requires personalities deviating from conventional human standards, objective judgment devoid of empathy, and criminally asymptomatic traits. Selected individuals undergo brain removal and integration; 247 known members exist across official media, residing interconnected within glass chambers in a secure underground facility beneath the NONA Tower, headquarters of the Ministry of Welfare. The physical structure contains 2,601 slots, yet only 200 members remain active simultaneously to sustain 24/7 operations. Publicly presented as an advanced supercomputer network, the Sibyl System conceals its true biocomputational nature—a collective of human brains. It originated between 2030–2049 as a tool enhancing employment aptitude exams via cymatic scans, evolving into a full crime-prediction apparatus by 2090–2100. The system takes its name from the Cumaean Sibyl of Greek mythology, an oracle granted immortality without eternal youth, reflecting its role as an all-knowing yet flawed entity. Members explicitly describe themselves as "prophet[s] right out of a myth." Sibyl enforces order primarily through real-time Psycho-Pass assessments, quantifying an individual's Crime Coefficient (latent criminality) and color-coded Hue (stress levels). Nationwide psionic scanners gather data, with Dominator weapons enabling instant field analysis. Dominators adjust function based on Sibyl's judgment: non-lethal paralysis for coefficients above 100, lethal force above 300, and system-override capabilities for direct threats to Sibyl. Beyond crime control, the system dictates socioeconomic functions, assigning careers via standardized exams, determining educational paths, and selecting government officials, reducing elected positions to figureheads. It isolates Japan internationally by closing borders to avoid diplomatic incidents involving foreigners' unreadable Psycho-Passes and sustains self-sufficiency through automated Hyper Oat farming. This isolation precipitated the exile of social critics, political dissidents, and other "undesirables" during implementation. Sibyl's development reveals persistent vulnerabilities and adaptations. Its foundational flaw—inability to scan criminally asymptomatic individuals—enables antagonists like Shōgo Makishima and Kirito Kamui to operate undetected. In response, the system attempts forcible recruitment, seen with Makishima's aborted induction and Arata Shindo's refusal. Internal instability occurs, notably during the Crisis of 2112 when its aggregate Crime Coefficient exceeded 300 due to compromised members, requiring emergency purges. To maintain secrecy, it falsifies Dominator judgments, eliminates personnel discovering its true nature, and manipulates law enforcement protocols. Foreign narratives expose jurisdictional blind spots, such as foreign embassies and military bases where Dominators malfunction. Later arcs introduce Bifrost—a rival entity challenging Sibyl's authority—and depict the system outsourcing physical operations to android proxies like Chief Joshu Kasei and subsequently Haruki Shirogane, who govern the Public Safety Bureau while masking Sibyl's involvement. Structurally, Sibyl adapts to critiques by incorporating diverse brains to enhance predictive accuracy, including former criminals like Kozaburo Toma and researchers like Misako Togane. It justifies authoritarian methods through utilitarian ethics, claiming actions ensure "the greatest good for the greatest number." Societal impacts include emotional atrophy in citizens, suppression of artistic expression, and erosion of personal agency. The proposed replacement, the Panopticon surveillance network, fails after intentional sabotage during the traffic-monitoring trial termed the "Season of Horror," cementing Sibyl's permanence.