Rizumu Amamiya, who later becomes Rizumu Toudou after marriage, serves as a central narrative figure. She first appears as a 14-year-old student in Yokohama, Japan, possessing a light complexion, orange hair typically secured by a pink heart-shaped accessory, and brown eyes. Her height shifts from 165 cm in her mid-teens to 175 cm by her late teens. Her preferred tomboyish, sporty style features sneakers, hoodies, and shorts, though she struggles with fashion coordination, frequently assembling gaudy outfits she finds appealing. Her personality blends high energy, determination, and occasional abrasiveness. She pursues goals passionately yet often becomes single-minded, particularly concerning her mother, the legendary Prism Queen Sonata Kanzaki, who vanished after performing the legendary Aurora Rising jump. Rizumu dedicates herself to mastering this jump, convinced it will reunite them, though this fixation initially causes her to dismiss friendships and neglect personal well-being. Academically challenged, she deems achieving a score of 70 miraculous. Despite claiming romantic expertise from books, she exhibits inexperience, reacting with intense flustered jealousy towards interactions involving Hibiki Toudou, whom she later marries. Her signature catchphrases are "Heart, charged!" and "I'm full of energy!". Her background reveals familial complexity. She is the daughter of Ryutaro Amamiya and Sonata Kanzaki, harboring long-standing resentment toward her father under the mistaken belief he drove her mother away. This emotional burden fuels her Aurora Rising obsession. She later gains an adopted sister, Kaname Chris, and an unnamed younger sister glimpsed in future visions. Her Prism Star journey begins at the Pretty Top dance school, where prior to her debut, emotional blockages stemming from her mother's absence prevented her from performing basic Prism Jumps. Her development centers on relationships and overcoming emotional barriers. A near-collision with Aira Harune at a mall sparks a pivotal connection. Initially dismissive of Aira's innate talent for Prism Jumps, Rizumu gradually bonds with her, recognizing friendship and teamwork's importance. Aira's fashion sense helps Rizumu connect emotionally with her performance outfits, enabling her to execute jumps like "Heartful Splash" and "Stardust Shower". This partnership, alongside Mion Takamine, forms the unit MARs. Conflicts arise when Rizumu's obsession resurfaces, nearly costing her health and friendships. A critical juncture occurs when Kei Asechi, her mother's former trainer, warns that performing the Aurora Rising requires sacrificing everything, leading Rizumu to momentarily reject Aira. Aira intervenes, helping Rizumu break free. Key achievements include successfully performing the Aurora Rising during the Prism Queen Cup semi-finals, though the exertion hospitalizes her. During recovery, her father reveals the truth about her mother's departure, resolving Rizumu's misplaced anger toward him. Although she doesn't win the Cup, witnessing her mother's recovery and welcoming Kaname as a sister marks significant personal closure. Her romantic relationship with Hibiki Toudou evolves from initial clashes fueled by his teasing into mutual affection, facing tension from Hibiki's sister, Kanon Toudou, who initially harbors animosity. Three years later, during Dear My Future, the 18-year-old Rizumu reignites MARs at Aira's suggestion, mentoring new trainees Prizmmy☆ and PURETTY. A significant revelation is her secret marriage to Hibiki a year and a half prior, concealed to avoid fan backlash. The eventual public announcement triggers initial fan disapproval, mitigated through trainee support, leading to wider acceptance. Kanon also reconciles, addressing Rizumu as "Onee-chan". Rizumu moves in with Hibiki and advises Aira on her romantic pursuits. A future vision depicts her on a honeymoon with Hibiki, her mother present holding her newborn sister.