Ako Shirabe, a 9-year-old third-year student at Public Kanon Elementary School, originates from Major Land where she holds the title of Princess as daughter to Queen Aphrodite and King Mephisto. Following Minor Land's takeover of her homeland and her father succumbing to evil influence, she fled to Kanon Town. There, she concealed her royal identity while living with her maternal grandfather, Otokichi. This trauma initially forged a cold, abrasive personality, causing her to lash out at others, particularly older classmates Hibiki Hojo and Kanade Minamino. Despite her youth, she displayed unusual maturity in complex situations. Her closest bond in Kanon Town is with Minamino Souta, Kanade's younger brother, who harbors implied romantic feelings she remains unaware of. Ako transforms into Cure Muse, initially operating behind a masked persona. As the Masked Cure, platform boots and a full-body disguise made her appear older, featuring a large black mask with purple accents, a black cape, and a heart-shaped gem on her forehead. She deliberately avoided speaking, allowing her Fairy Tone partner, Dodory, to communicate. Frequently aiding the other Pretty Cures against Negatone enemies using barriers and restraints created from colorful piano keys, she maintained an aloof demeanor and insisted she was not their ally. Revealing her true form as Cure Muse unveiled bright orange hair that grows extremely long, magenta eyes, and an elaborate yellow-themed outfit comprising a ruffled blouse, balloon skirt, hip ribbons, knee-length boots, and a shawl bearing the Cure Module. This form retains the heart-shaped forehead gem and incorporates Dodory into her transformation. She wields the Cure Module for attacks instead of a dedicated purification weapon. With her secondary Fairy Tone Shiry, she performs techniques like Shining Circle and Sparkling Shower. She later attained an upgraded form, Crescendo Cure Muse, featuring lighter, thicker curled hair, larger ribbons, simplified skirt layers, wing-like protrusions, and a predominantly white and pale yellow color scheme. Her journey as Cure Muse began the day her father, under evil control, stole the Legendary Score. She adopted the masked persona specifically to avoid confronting him directly in battle. When forced to reveal her identity, she struggled to fight him until gathering the courage to strike him, breaking the evil's hold and restoring his true self. After this, she fully joined the Suite Pretty Cure team alongside Cure Melody, Cure Rhythm, and Cure Beat, shedding her cold exterior to reveal a sweet, considerate nature with a love for singing and music. Despite her royal status, she prefers being addressed simply as Ako and rejects formal titles. In "Precure All Stars New Stage: Mirai no Tomodachi", Ako appears as Cure Muse with the Suite Pretty Cure team. They participate in the initial battle against the villain Fusion in Yokohama, resulting in Fusion's body parts scattering across the city. Later, while searching for these fragments with her team and the Smile Pretty Cure team, she encounters Ayumi Sakagami and her Fu-chan creature. Cure Muse battles Fusion's spawn alongside the other Cures when Fu-chan grows hostile and attacks the city. She fights alongside multiple Pretty Cure teams, including Heartcatch and Fresh, to stop the rampaging spawns. During the climax at the tower, she witnesses Ayumi's transformation into Cure Echo and participates in the united effort to confront the reborn Fusion. Cure Muse contributes to the final battle where the combined teams, empowered by Miracle Lights from the city's citizens and Fu-chan's sacrifice, ultimately defeat Fusion. Ako Shirabe is the youngest mainline Pretty Cure in the franchise. Her surname "Shirabe" relates to "tone" or "playing music", fitting Suite Pretty Cure♪'s musical theme, while "Ako" derives from "acoustic". Her Cure Muse name references the Greek muses of artistic inspiration.