Captain Nezumi is a Marine captain of the 16th Branch in the East Blue. Highly corrupt, he covered up the vast majority of Arlong's actions in the Conomi Islands in exchange for bribe money.

Due to his actions, he can be considered the secondary antagonist of the Arlong Park Arc. He is also the one responsible for officially making Monkey D. Luffy a wanted criminal to the World Government by requesting his first ever bounty.