Shirabe Ako, also recognized as Cure Muse, stands as a central protagonist within her series and the Princess of Major Land. Initially concealing her identity as the enigmatic Masked Pretty Cure, she covertly aids others while masking her true intentions. In her civilian life, she appears as a third-year elementary student with striking orange eyes, magenta-framed glasses, and a short bob hairstyle, frequently clad in practical attire such as pink shirts layered beneath purple overalls. The invasion of her homeland by Minor Land hardens her demeanor into a cold, abrasive shell, driven by the conviction that she alone must shoulder the burden of salvation. This exterior softens upon joining the team, unveiling a compassionate spirit, a deep passion for music, and wisdom surpassing her youth.

Her metamorphosis into Cure Muse is activated by the Cure Module and Fairy Tone Dodory, heralded by the incantation "Let's Play! Pretty Cure Modulation!" This transformation dramatically alters her appearance: her hair cascades into vibrant orange strands adorned with yellow ribbons, her eyes shift to magenta, and she dons a yellow-and-white ensemble featuring a ruffled peplum skirt complemented by golden accessories. As the Masked Cure, she wears a sleek purple-and-black bodysuit with a heart-embellished mask and elevated platform boots, crafting an illusion of maturity. Her arsenal includes conjuring barriers woven from rainbow-hued piano keys and unleashing attacks like Shining Circle and Sparkling Shower, channeled through the Cure Module and Fairy Tone Shiry. She later ascends to her Crescendo Cure Muse form, sprouting ethereal feathery wings and draped in a regal golden cape.

Key relationships shape her journey: her father Mephisto, corrupted by the malevolent Noise, drives her initial secrecy, while her mother Aphrodite, the sovereign Queen of Major Land, anchors her royal lineage. Residing with her grandfather Otokichi in Kanon Town, she shares a close bond with classmate Minamino Souta, oblivious to his unspoken romantic affections. Her path navigates reconciling royal obligations with her fierce desire to shield loved ones, culminating in openly battling alongside teammates once Mephisto is freed from corruption.

The film *Suite Pretty Cure♪: Torimodose! Kokoro ga Tsunagu Kiseki no Melody!* showcases her harnessing amplified powers through unified Fairy Tones, mirroring her evolution. Supplementary novels expand her narrative, illustrating collaborative assaults like Passionate Harmony alongside fellow Cures. Distinctive design elements—her civilian-form glasses and absence of a primary weapon—set her apart from comrades. Her name echoes musical roots: "Shirabe" signifying "tone" or "musical performance," and "Ako" originating from "acoustic."

Her arc traverses overcoming self-imposed isolation, embracing camaraderie, and harmonizing royal lineage with personal bonds. This growth is marked by her evolution from a shadowed ally to a pivotal team cornerstone, wielding tactical brilliance and heartfelt resolve to safeguard interconnected worlds.