One Piece: Defeat Him! The Pirate Ganzack

As Luffy and his companions, Zoro and Nami are starving on their small boat, they were attacked by a gigantic monster all of a sudden. Nami was shocked, while Luffy and Zoro were washed up on the shore. While there, they met a young girl named Medaka, and found out about the history of the island. It turns out that the ruthless Pirate Ganzack has taken away all the men in the village and ended up making them slaves, which included Medaka's father.