Kōhei Katsuragi serves as one of Class 1-A's representatives. His tall, well-built frame and bald appearance, caused by a childhood illness, create an intimidating presence. Academically accomplished through diligent effort, he exhibits a serious, rule-oriented personality. He emphasizes proper conduct, reprimanding classmates whose actions risk class points. Despite this stern demeanor, he occasionally reveals vulnerability, like when agonizing over choosing a birthday gift, showing hesitation in personal matters. His leadership prioritizes maintaining Class A's advantage conservatively. During the uninhabited island survival test, he formed a covert alliance with Class C's Kakeru Ryūen, believing it ensured Class A's victory. This strategy failed due to unforeseen interference orchestrated by Kiyotaka Ayanokōji, resulting in Class A placing third. The failure severely damaged his standing among classmates and eroded his influence, sparking vocal discontent. His relationship with co-representative Arisu Sakayanagi evolved significantly. Initial collaboration masked underlying tensions between his cautious conservatism and her aggressive tactics. Following the island test failure and his diminished authority, Sakayanagi consolidated power by expelling his key supporter, Yahiko Totsuka. This action, combined with threats of further repercussions, compelled Katsuragi to submit entirely, becoming a loyal subordinate who follows her directives without question. In the cruise ship special exam, he implemented the defensive "castle gate" strategy, instructing classmates to remain completely silent during group discussions to prevent leaks and ensure equal point distribution. He defended this tactic prioritizing Class A's lead, despite criticism from other classes, including Honami Ichinose, for hindering necessary communication. Facing diminished status and influence within Class A, he eventually accepted an offer from Kakeru Ryūen to betray his class. He transferred to Ryūen's class (formerly Class C) seeking an opportunity for revenge against Sakayanagi. This shifted their relationship from mutual disdain to cooperation against a common adversary. After the transfer, Ryūen revealed Ayanokōji's full capabilities to Katsuragi, who then confronted Ayanokōji, warning him that his hidden abilities would inevitably be exposed, disrupting his desired ordinary school life. His birthdate is August 29, his height is 180 cm, and he frequents locations like the Keyaki Mall and classrooms.