The "section chief" of Problem Solver 68 and a 3rd year student at Gehenna Academy.
Unlike the other members of Problem Solver 68, though, Kayoko is not one with ill intentions. However, she is often misunderstood as a delinquent simply due to her naturally intimidating facial expressions and appearance. She normally prefers to keep silent about this topic, as it likely leads to furthering her terrifying image.