Ryūtarō Sera, a third-year Cypress Group student and Okazan Futsal Club member, balances strict self-discipline with quiet compassion. His stoic exterior and relentless work ethic stem from a deeply ingrained sense of masculine responsibility, yet he earns admiration for his unwavering support of teammates. This protective instinct sharpens toward first-year regular Saku Hasumi, whose novice status on the senior squad draws Ryūtarō’s watchful guidance.

Between futsal drills, he fuels his passions for vintage motorcycle magazines, weight training, and soulful Enka ballads—a musical taste nurtured by his grandmother. A meticulously maintained 400cc motorcycle, acquired through his bond with a local shop owner, reflects his appreciation for craftsmanship. His robust appetite favors meat-heavy meals and ramen, though he endures teammate Tsubaki Yukinaga’s experimental cooking without complaint. Blunt honesty anchors his interactions, clashing with distaste for flirtatious behavior.

Aikido’s principles shape both his agile futsal maneuvers and disciplined daily routines. While holding himself to exacting standards, he quietly mentors peers, blending stern expectations with steadfast encouragement. His name echoes this duality: "Ryūtarō" merges the ferocity of dragons, the grandeur of greatness, and the calm of serenity, while "Sera" intertwines worldly grounding with moral integrity, mirroring his aspirational yet pragmatic spirit.