Captain Nezumi

Fittingly for his name, Nezumi is a lean, dark-haired man whose features strongly recall a mouse. His eyes stay perpetually narrowed, and his facial hair amounts to a thin goatee plus six long, wiry whiskers along his upper lip. He has heavily modified his Marine uniform, reshaping the regulation cap into a mouse-eared cowl attached to a buttoned greatcoat that falls to his feet, finished with a belt and blue epaulets. In the anime his coat takes on a bluish-grey shade.

As his rodent looks suggest, Nezumi is cowardly, opportunistic, and devoid of integrity. His avarice runs so deep that he will scheme alongside criminals for the long haul, swallow his own disgust toward Fish-Men, and even open fire on civilians if money is on the line. Day to day he carries a smug, superior manner, certain his rank by itself should earn deference; the moment he is overpowered he grovels and pleads until he can slip away to safety. His trademark laugh, "Chi chi chi chi," echoes the usual sound effect for a squeaking mouse.

For some time Nezumi and his unit looked the other way on the Arlong Pirates' grip across the Conomi Islands, taking monthly payouts in return. Although Arlong treated the Marines as honored guests, Nezumi kept his visits to Arlong Park brief, unnerved by the Fish-Men. Following one such payment, Arlong tipped him off to a fortune buried in Cocoyasi Village, the savings Nami had amassed across eight years to purchase the village's freedom. Branding it stolen goods, Nezumi marched his men there and forced Genzo to guide them to Nami's home, then ransacked the place. When the villagers grasped that the Marines were Arlong's partners, Nezumi ordered an armed response, and Nojiko was shot in the side. He soon unearthed the hoard of 93,000,000 berries and gloated over it.

His cruelty pushed Nami and Genzo to their limits, which set the Straw Hats on their assault that demolished the Arlong Pirates. Seeing Arlong Park fall, Nezumi tried to seize the credit and the treasure for himself, only to be thrashed by the Straw Hats, with Nami landing the last hit and demanding he return the money and aid the ruined communities. Terrified, he complied, then withdrew to a safe distance and swore vengeance against Luffy. He later reported the affair to his superiors, supplying only a harmless photo of a smiling Luffy, which nonetheless prompted Marine Headquarters to set a 30,000,000 berry bounty, a figure without precedent in the East Blue. In the non-canon novel ZORO, he is depicted taking bribes near Nazawaka City and faking an investigation before his promotion to Captain.