Kurea Ōba, a first-year student at St. Catalano Girls' High School and member of its climbing team, leverages her background as a former ballet dancer in her climbing. This foundation grants her exceptional balance, precise leg movements, and elegant hip control, earning her the nickname "Ballerina of Rock" and enabling technically refined wall maneuvers.

She nurses a fierce rivalry with Konomi Kasahara, rooted in their childhood ballet school days where Konomi consistently outperformed her. Driven by this history, Kurea focuses intensely on defeating Konomi in climbing, initially believing her greater experience guarantees victory. Her perfectionism fuels outwardly aggressive behavior, especially towards Konomi, whom she frequently provokes with competitive taunts. Harsh comments during speed climbing training once reduced Konomi to tears, an action Kurea later regretted. Despite her abrasive exterior, she secretly acknowledges Konomi as a worthy rival and respects her abilities.

Kurea's development emerges through setbacks. At the Kanto Bouldering Championship, after initially dismissing Konomi as a novice, repeated failures on a challenging semifinal route trigger a crisis when she recognizes Konomi's superior analytical skills. Confronting this, Kurea openly admits Konomi's superiority, leading to an emotional release. She strategically shifts focus to achievable goals for her team's benefit, marking a turning point where she moves beyond pure rivalry to acknowledge others' strengths.

Her growth continues as antagonism evolves into supportive encouragement. When Konomi suffers a breakdown during training camp, Kurea intervenes directly—slapping her—to spur her out of depression, followed by genuine encouragement. This act, while seemingly harsh, demonstrates Kurea's investment in Konomi's resilience and reflects her complex, underlying approval. Her journey illustrates a shift from one-dimensional competitiveness to a more nuanced understanding of rivalry and mutual respect.