OVA
Description
Kaguya Shinjūin is a central character in the world of jet racing, known as the ace Jetter for the team Dress, representing the prestigious Musashino Girls High School. She is the racing partner of her devoted teammate, Kuromaru Manpuku, with whom she competes in high-stakes races along the Kandagawa River.

Physically, Kaguya is an 18-year-old girl with a striking and elegant appearance, standing 165 centimeters tall. She possesses long, thigh-length silvery-gray hair that is typically styled into four distinct curled sections, resembling drills, and secured with a butterfly-shaped hair clip. Her bright violet eyes complement her aristocratic features. Her school attire consists of a lavender four-button jacket and a long purple skirt that is longer in the back and shorter in the front, allowing for easier movement, paired with burgundy high-heeled shoes. For racing, she wears a sleek, full-body black and dark purple wetsuit adorned with small red triangular accents on the neck and shoes, though in the anime adaptation she does not wear her signature butterfly clip while in this racing gear.

Kaguya's personality is initially presented as that of a stereotypical, confident, and proud young heiress. She comes from a wealthy and influential family and expects a certain level of deference from those around her. This is evident in her first encounter with the protagonists, Rin Namiki and Misa Aoi, when she demands they vacate the harbor so her team can practice, as she believes her status grants her priority. Despite this surface-level arrogance, Kaguya is fundamentally fair and honorable, readily suggesting a jet race to settle disputes rather than relying solely on her authority.

Beneath her lofty exterior lies a deeply caring and loyal individual, particularly towards those she considers close. Her most defining trait is her profound bond with Kuromaru Manpuku, who is not only her teammate but also her personal maid, coming from a family that has served the Shinjūin household for generations. Kaguya is fully aware of Manpuku's background as a shinobi and treats her as an equal partner and a best friend rather than a servant, often treating her to meals at all-you-can-eat buffets. This loyalty is so powerful that Kaguya is willing to sacrifice her own ambitions, such as forfeiting a crucial race in the Kandagawa Cup, to protect Manpuku from collapsing due to overwork and exhaustion.

Kaguya's primary motivation in the narrative, especially within the video game's storyline, is to save her school's jet racing team. She enters the Kandagawa Cup to prevent her father, who serves as the school's principal, from disbanding the team. This drive for victory initially puts her at odds with other teams, including the main protagonists, whom she and Manpuku defeat early on to claim ownership of the river for practice. However, as the story progresses, Kaguya undergoes significant development, learning to temper her cutthroat ambition with empathy and sportsmanship. Her realization that there is more to jet racing than just winning or losing becomes a central theme of her arc. She evolves from a haughty rival into a respectful adversary, as seen when she gracefully acknowledges the skills of Rin and Misa after losing the Kandagawa Cup to them and vows to improve further.

As a racer, Kaguya is renowned for her exceptional skill, strategic mind, and rigorous training regimen. She maintains her physical conditioning through intense workouts involving weights, gym equipment, running, and even unconventional methods like bungee jumping. Her racing style is defined by confidence and efficiency; she famously reserves her jet's boost function for only the most necessary moments, a tactic that demonstrates her belief in her own raw ability and physical conditioning to outpace her opponents. Her key relationships—with her unwavering partner Manpuku, and the rival teams like the Kandagawa Jet Girls and Grindcore—are central to the story, testing her values and forcing her to grow from a proud princess into a leader who champions teamwork, integrity, and the true spirit of the sport.