Natsuki Oikawa is a sixth-grade ballet dancer whose exceptional technical skill surpasses her peers, though her expressive performances often fall short. She possesses black hair styled in waist-length braids and blue eyes. Raised in a family of mechanics, an unconventional background for ballet, she felt like an outsider and endured classmates' ridicule. This fueled her perfectionist, serious nature and relentless drive to be the best through rigorous effort.

Proud and intensely focused on precision, Natsuki sees ballet as self-expression, not a quest for external validation. This dedication manifests as a need to control every performance detail, creating challenges in conveying emotional depth despite her technical mastery. She shares a significant artistic connection with Junpei Murao, recognizing his complementary focus on raw emotion as aligning with her belief in expression through movement. This mutual understanding fosters a strong professional and personal bond, hinting at developing romantic feelings. Their partnership enables perfect synchronization, embodying their shared dance philosophy.

Her development centers on navigating personal and professional challenges within ballet. Initially socially reserved due to her background and singular focus, interactions with peers, especially Junpei, gradually spur growth. She begins confronting her emotional limitations and the pressures of perfectionism. This journey extends beyond the anime, continuing in the manga where her ballet dedication and evolving relationships are further explored.