Kaguya was once the princess of the Lunarians, a race inhabiting the Moon. She was exiled to Earth over a millennium ago for using the forbidden Hourai Elixir to achieve immortality. Upon arriving in central Japan, she was discovered by a bamboo cutter and lived among humans, a group she had previously held in disdain. Despite the Lunarians' contempt for humans, Kaguya grew to love her new life on Earth. Her extraordinary beauty attracted many suitors from across Japan, but none could fulfill her Five Impossible Requests.
Years later, emissaries from the Moon arrived, announcing that Kaguya had been pardoned and was to return. However, Kaguya had developed a deep affection for Earth and did not wish to go back to the lunar capital. With the aid of her friend Eirin, Kaguya evaded the emissaries and sought refuge in Gensoukyou. They settled in an ancient mansion named Eientei, hidden deep within a secluded bamboo forest, starting a new chapter of exile.
During the events of Imperishable Night, Kaguya was concealed in a secret passage along with the true moon by Eirin to prevent any Lunarian recovery teams from finding her. The heroines eventually uncovered her location and challenged her to restore the full moon to Gensoukyou. After being defeated, Kaguya attempted to break the spell of the imperishable night by unleashing her power of eternity. Ultimately, she conceded, and the true moon was restored.
Today, Kaguya resides in Eientei, leading a carefree life. She occasionally hosts exhibitions of Lunarian treasures for the residents of Gensoukyou to admire. Her prolonged isolation has left her feeling lonely, and she delights in sharing stories with any visitors who come to see her.
