Maruzensky is a horse girl attending Tracen Academy and a member of Team Rigil. She possesses a vibrant and outgoing personality, often speaking in a retro slang style and exuding a sisterly, caring demeanor toward her peers. Her most defining trait is her sheer love for speed and the sensation of the wind on her face during a race. She is widely regarded as a speed demon whose running style is so overwhelming that she earned the nickname "supercar" and is sometimes called a "monster" on the track.

Her background is marked by a deep sense of unfulfilled potential. In her early career, she dominated every race she entered, winning by massive margins despite competing on the same track as other outstanding horse girls. However, due to regulations that prevented her from entering the prestigious Japan Derby, she was denied the opportunity to prove herself against the strongest rivals of her generation. This left her feeling isolated at the top and yearning for a true challenge. Her core motivation throughout the story is to find a worthy opponent who can push her beyond her limits and to pass on the joy and thrill of running to the next generation.

In the narrative of Uma Musume: Cinderella Gray, Maruzensky serves as a legendary figure from a past era who reemerges to face the rising star Oguri Cap. Her role is that of a formidable rival and, ultimately, a mentor figure. The climax of her arc occurs in the Japan Cup, where she ignores the warning signs of a fragile leg to engage in an all-out battle with Oguri Cap. That race becomes her final, explosive performance—a symbolic passing of the torch. After retiring, she remains at the academy as a living legend, offering guidance and encouragement to younger horse girls such as Special Week.

Key relationships define her journey. She shares a deep mutual respect with Symboli Rudolf, recognizing each other's strength and the emptiness of being unmatched. With Oguri Cap, she forms a bond of intense rivalry and later a almost familial sense of legacy, as she sees in Oguri the successor who can carry forward the spirit of true racing. Her relationship with Special Week is more affectionate, almost like an older sister or mother figure.

Her abilities are centered on phenomenal speed and acceleration. She is most dangerous in the early and middle stages of a race, where she can take the lead and set an impossible pace. Her signature skills involve shifting to a higher gear in the latter half of a race, particularly in mile and middle-distance events, allowing her to maintain or increase her lead. Despite her overwhelming power, she is not arrogant; she treats her competitors with respect and is well-liked by everyone. Her development is a journey from isolated dominance to selfless legacy, embracing the role of a guide for the future generation.