Shion is a French friend of Momoka Nishizawa, both of whose families are wealthy and noble. She inherited the dragon book after her parents passed away and was able to read it despite nobody else being able to. When she looked at the book, the words appeared in her head, and she could hear the voice of an earth dragon. Shion also had the ability to summon the tails of dragons to spread across the world. She later invited Momoka and Tamama to her home in France, where she transformed the Keroro Platoon into dragon warriors. However, when Keroro and the Hinatas arrived to help Momoka, they were unable to capture Keroro and transform him. Shion then traveled with the Hinatas and Keroro to destroy the Earth Dragon's egg. During this journey, she transformed Keroro to help his friends. When the Earth Dragon was summoned and threatened to destroy the Earth, it seemed as though Shion sacrificed herself, but in reality, she and the Platoon members were safe and returned to their original selves. Afterward, Shion attended school with Terara, the Keronian form of the Earth Dragon, wearing her hat and occasionally visited by other Keronians and their partners.