Mireille is a Wavemaster who uses the same avatar as Mistral and loves of treasure-hunting. She is a good friend and ally of Rena and Shugo and is knowledgeable of The World. Her true identity is Mirei Kurokawa (黒川深鈴, Kurokawa Mirei?), the daughter of Mayumi Kurokawa, who was originally the Wavemaster Mistral and gave the avatar to her daughter.
Text from wikipedia
Character is error.