Kae Hiiragi, a first-year student at Marehoshi Private School’s Takao Branch, balances her role in the idol unit KiRaRe with a quiet, introspective nature. Her striking pink hair and sapphire-blue eyes complement a wardrobe of frilly, feminine attire, often accented by a prominent black ribbon. As part of KiRaRe, her style shifts through unit-specific designs: an indigo star hairpin, flowing dresses with ruffled sleeves, and berets paired with bow-ties underscore her eclectic flair.

Social interactions have eluded Kae since elementary school, leading her to cherish solitude and independent living. Yet within her secluded space, she hones remarkable mechanical ingenuity, crafting intricate inventions. Online, she adopts the alias "Dark Shadow Princess," channeling her passion for gaming and technology into a bold alternate persona.

A pivotal bond with Survival Game Club member Kasumi Honjou—whom Kae affectionately dubs "Angel," inspired by Kasumi’s "Thousand Kill Angel" moniker—anchors her emotional growth. Kasumi’s reciprocal nickname, "Princess," fosters a trusting dynamic that gently nudges Kae toward meaningful connections.

Driven to save the Lyrical Tradition Dance Club (later renamed KiRaRe) from disbandment, Kae leverages her technical prowess to bolster the group’s survival. Her contributions during recruitment drives and Prism Stage competitions reveal a deepening commitment to teamwork, even as shyness lingers in non-idol settings.

Born January 5 with blood type O, Kae’s surname, Hiiragi ("holly"), mirrors her resilient yet understated presence. Her journey navigates the tension between solitary inclinations and the collaborative demands of idol life, marking gradual strides in social engagement while preserving the quiet independence that defines her.