One Piece: Giant Mecha Soldier of Karakuri Castle (2006)

Cast: Mayumi Tanaka, Kazuya Nakai, Akemi Okamura, Kappei Yamaguchi, Hiroaki Hirata, Kazue Ikura, Yuriko Yamaguchi, Goro Inagaki, Koji Kato, Keiichiro Yamamoto

The Straw Hats visits an island, known as Mecha Island, where a fisherman sings an old folk song about a Golden Crown. Searching for that mysterious treasure, they find a hidden entrance into the isla…