Kaguya Yumemizuki is a mysterious girl who washes ashore on Wyndaria Island in the anime series 'Shining Hearts.' She suffers from amnesia and is found by Rick, the protagonist, and his friends. Kaguya is central to the story as her lost memories are tied to the magical occurrences on the island. Her gentle and ethereal presence brings a sense of calm, yet her enigmatic past introduces intrigue and adventure. As the series progresses, Kaguya’s true identity and her connection to the island’s secrets are gradually revealed, making her a pivotal character in the unfolding narrative.