Mr. 9 is Vivi's partner during her undercover mission in Baroque Works. He's got this distinctive crown decorated with nines and fights using acrobatics and steel bats. The Straw Hats first run into him and Vivi when the two are hunting Laboon the whale for food, which doesn't exactly go well. Later, after Mr. 9 and Vivi lose their Log Pose, Luffy's crew gives them a ride to their destination anyway.
Things fall apart when Mr. 5 and Miss Valentine blow Vivi's cover. Mr. 9 tries to buy her time to escape, but he ends up taking the loss against Mr. 5. Despite his effort, he can't quite pull it off.
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