Ryuudai Jinno is a third-year student at Fukuhou Technical High School and a member of the boys' volleyball team. His given name "Ryuudai" fuses the characters for "dragon" (龍) and "great" (大), while his surname "Jinno" blends "deity" (神) and "wilderness" (野). He possesses brown hair trimmed to ear length and striking pink eyes.

Within the story, Jinno serves as a rival competitor against the protagonists' team during high school tournaments. Post-graduation, he advances his volleyball career at Keisai University, featuring in the sequel novels "next 4years." At Keisai, he joins teammates like Yumihake Atsushi ("九州の弩弓") and Yamabuki Seijirou, confronting opponents including Keiyo University and Hachiyo University in collegiate league matches.