Yousuke Oohira is the goalkeeper for Shinsei High School's soccer team and a third-year student with a notably large physical build. Initially positioning himself as the self-proclaimed "boss" of the school, this changes after he loses a physical confrontation to Shingo Tamai, leading him to gain respect for Shingo.

Yousuke displays a genial and reasonable personality, contrasting sharply with Shingo's impulsiveness. Their relationship evolves into one defined by mutual criticism and deep loyalty. Yousuke frequently calls out Shingo's reckless or immature behavior while remaining his closest supporter. This dynamic casts Yousuke as the straight man, providing grounding perspective to Shingo, though their interactions often involve heated exchanges stemming from their differing approaches. Despite this friction, they function as vitriolic best buds whose bond strengthens through shared training and team challenges.

Beyond goalkeeping, Yousuke offers tactical balance to Shingo's impulsiveness, using his level-headedness to stabilize team decisions. His encouragement and critical feedback during practices and matches significantly contribute to Shingo's growth. One demonstration of his dedication involves training with a blindfold to enhance his ability to intercept balls through sound and instinct alone, showcasing both physical skill and perseverance.

His leadership manifests through reliability during matches, where his presence as goalkeeper provides defensive security. This consistency reinforces team cohesion, particularly during high-pressure games against rival schools. Yousuke's journey reflects a focus on collective achievement rather than individual prominence, with his development tied closely to his evolving partnership with Shingo and unwavering commitment to the team's success.