One Piece: Giant Mecha Soldier of Karakuri Castle (2006)
ActionAdventureAnimationComedyFantasyScience Fiction
Director: Konosuke Uda · Writer: Masahiro Ito
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 island. The island's leader, Ratchet, impressed with the find and in search of the Golden Crown himself, invites the crew to join him in his search and the crew along with Ratchet and his henchmen enter the cave. As it turns out, the islands true form, is that of a giant turtle. Ratchet, who had known this all along, uses his mechanical castle to take control of the turtle, in order to use it, to take over the world. Now the Straw Hats have to stop not only Ratchet, but also the helpless turtle, from crashing into a nearby island.
Director
Konosuke Uda
Cast
Mayumi Tanaka
Monkey D. Luffy (voice) 
Kazuya Nakai
Roronoa Zoro (voice) 
Akemi Okamura
Nami (voice) 
Kappei Yamaguchi
Usopp (voice) 
Hiroaki Hirata
Sanji (voice) 
Kazue Ikura
Tony Tony Chopper (voice) 
Yuriko Yamaguchi
Nico Robin (voice) 
Goro Inagaki
Dr. Rachet (voice) 
Koji Kato
General Maji (voice) 
Keiichiro Yamamoto
Colonel Honki (voice) 
Hisako Kyoda
Roba (voice) 
Takeshi Aono
Gonzou (voice) 
