Rokusuke Kōenji attends Advanced Nurturing High School as a student in Class D. Recognizable by his blonde hair, maroon-gradient eyes, and tall, well-built frame, he typically wears the standard uniform. His immense wealth as heir to the Kōenji conglomerate fuels a self-entitled and arrogant demeanor. This privileged background fosters an egotistical nature, driving him to prioritize personal freedom and shun group efforts unless they serve his self-interest. His lack of cooperation and disregard for teamwork led directly to his placement in Class D, reserved for students with significant social or behavioral defects. Despite disinterest in class advancement, he devised a strategy where third-year students transferred private points to him in exchange for future monetary reimbursements, a plan potentially disrupted by new school rules. Kōenji consistently displays exceptional academic and physical prowess. He achieves high exam scores without relying on memorization, demonstrating innate intelligence and sharp observation. During a cruise ship special test, he correctly identified his group's VIP within a day, securing 50 class points and 500,000 private points for himself, seemingly motivated by avoiding prolonged participation rather than aiding his class. His physical abilities include acrobatic agility, such as navigating forests by leaping between trees during a survival test, and swimming at speeds comparable to world-class athletes. He effortlessly blocked a punch from skilled fighter Ken Sudō and displayed superior strength, like performing a 200kg bench press. These capabilities position him as a latent threat, acknowledged by leaders such as Class B's Honami Ichinose. His personality is marked by extreme narcissism; he frequently admires his reflection and dismisses others' opinions. He assigns nicknames to peers: "Elevator Boy" for Kiyotaka Ayanokōji, "Red Hair" for Ken Sudō, "Little Girl" for Arisu Sakayanagi, and "Dragon Boy" for Kakeru Ryūen. Though typically selfish—abandoning his class during the island survival test cost them 30 class points—he exhibits rare, unexpected kindness. He defended Mei Yū after she was pushed by Yōsuke Hirata, escorting her to safety and criticizing Hirata's lack of apology. He later sent gifts to Mei during her absence, hinting at a capacity for subtle reciprocity beneath his aloof exterior. Kōenji's role in class dynamics is unpredictable. He ignores directives from leaders like Suzune Horikita and openly mocks classmates, yet his actions sometimes yield accidental benefits, like his correct VIP guess on the cruise. His rivalry with Ayanokōji intensifies, with both recognizing each other as intellectual and physical equals; the competing legacies of their fathers further fuels this tension. Though largely disengaged, Kōenji strategically ensures self-preservation, such as redirecting negative attention during expulsion votes to avoid being ousted. His ultimate aspiration centers solely on maintaining "true freedom," with no explicit interest in reaching Class A beyond leveraging the system for personal gain.