Kaoru Ryūzaki, a 9-year-old idol from Ehime, radiates bright energy and youthful innocence. Her orange hair and topaz eyes complement her summer-themed persona, aligned with her Cancer zodiac. Driven by a heartfelt desire to uplift others, she tackles challenges with unwavering enthusiasm—even her comically persistent attempts at cooking, which she approaches with undeterred joy. Standing 135 cm tall, she first met the Producer in a park, swiftly aiding him with scattered documents and revealing her background in children’s TV programs and maternal interviews. Though initially uncertain about idolhood, she embraced it wholeheartedly upon discovering its potential to spread joy, forging a close mentor-student bond with the Producer, whom she affectionately calls "Sensei." Her attachment to their relationship shines in moments like retracing her school route to ensure he could walk her home. Kaoru thrives among peers, sharing school and idol activities with friends Mai Fukuyama, Chika Yokoyama, and Nina Ichihara. She admires Ai Togo as an older sister, though their bond occasionally sparks playful clashes, like her misguided role-play attempt to "arrest" Ai. A unifying presence in units like CuriouStar, Marine Party!!, and Little Marching Band Girls—where she plays snare drum—Kaoru also anchors groups such as Canary Summer and U149, openly voicing worries about outgrowing the latter’s 149-cm limit. Her narrative blends whimsy and growth, from recounting a classroom mantis scare to leading spirited "talk battles," all while balancing her natural cheerfulness with earnest efforts to support her teams. Physically, she weighs 34 kg with measurements of 68-53-70 cm, her sunflower-yellow image color mirroring her vibrant spirit. Right-handed and prone to dropping the "su" in polite speech, Kaoru’s distinct voice extends across manga and collaborations, cementing her role as an emblem of youthful exuberance.