Yuuki Shibayama is a first-year student at Nekoma High School and the libero for the boys' volleyball team, wearing jersey number 12. He stands 162.5–163 centimeters tall and weighs approximately 53 kilograms, born on December 16th. As a developing player, his first-year skills result in limited court time during high-stakes matches, particularly against stronger opponents. From the sidelines, he actively supports and encourages his teammates. Shibayama's role emphasizes reliability and diligent observation; he meticulously scours game footage during free time to refine his techniques and deepen his understanding of volleyball dynamics. During Nekoma's Tokyo Qualifiers semifinal against Fukurōdani Academy, he closely observes how Nekoma's back-row receivers leverage Kuroo's blocks against Bokuto's spikes, demonstrating his focus on defensive strategy and team coordination even while benched. His approach prioritizes hard work and incremental growth over innate talent, reflecting his commitment to team contribution. Personality-wise, Shibayama is quiet and unassuming, preferring actions over words to demonstrate his dedication. He exhibits strong loyalty and protective instincts towards teammates, coupled with a keen emotional awareness of others. His sharp observational skills enable him to read opponents' movements and anticipate plays, vital traits for his libero position. He adapts methodically to new situations, relying on meticulous attention to detail and creative problem-solving under pressure.