Mr. 9 is Princess Vivi's assigned male partner during her infiltration within Baroque Works. He wears a crown decorated with nines and fights with acrobatics coupled with steel bats. He and Vivi meet the Straw Hats while trying to kill Laboon the whale for food. The Straw Hats give them a ride there later after they accidentally lose their Log Pose. After Vivi is exposed by Mr. 5 and Miss Valentines Day, Mr. 9 tries to hold them off to allow her to escape. He is defeated by Mr. 5.
(Source: Wikipedia)