Kaku is a significant character in the anime and manga series One Piece. Initially introduced as a shipwright of Water 7's Galley-La Company, he is later revealed to be an undercover agent of CP9, a secret government organization specializing in espionage and assassination. Known for his square-shaped nose and acrobatic abilities, Kaku becomes one of the main antagonists during the Enies Lobby arc, where he battles against the Straw Hat Pirates. His Devil Fruit power allows him to transform into a giraffe, adding to his combat prowess.