Yu Kamimura/Underworld

Yu Kamimura (上村 優) is a mysterious young woman who lives in the Underworld, appearing in the film Kamen Rider × Kamen Rider Wizard & Fourze: Movie War Ultimatum. She is able to become the Young Masked Belle Poitrine (美少女仮面ポワトリン) by using the Orgel Pendant (オルゴールペンダント) and shouting out "Cosmo Magic Metamorphose!" (コスモマジック・メタモルフォーゼ！). As Poitrine, she is able to use magic and use the Belle Sabre (ベルサーベル).

Basis
Yu Kamimura/Young Masked Belle Poitrine is a homage to Shotaro Ishinomori's La Belle Fille Masquée Poitrine which was part of the Toei Fushigi Comedy Series.

Portrayal
Yu Kamimura is portrayed by Mari Iriki (入来 茉里).