16th Branch

This base anchors the 16th Marine division in the East Blue and falls under the command of Captain Nezumi. Its design differs across media: the manga keeps it mostly obscured but tops it with a large mouse-head model crowned by ears and a tail that becomes a Marine flag, the anime renders it as a squat blue dome ringed by smaller towers, and the PlayStation game depicts it as a green tower with a cannon-bearing companion structure.

The branch oversees the Conomi Islands, the region that includes Cocoyasi Village where Nami grew up. Far from protecting the area, it deliberately looked the other way while the Arlong Pirates oppressed the islands, a blindness purchased through Arlong's regular bribes. When Arlong learned that Nami had saved enough money to buy back her village, he tipped off Nezumi, who seized the entire buried hoard of ninety-three million Berries. After the Straw Hats toppled the fish-men crew, Nezumi tried to grab Arlong's treasure for himself, only to be thrashed by Zoro and forced to return what he had stolen. Humiliated, he fled back to the base to report Luffy to Marine Headquarters.

Captain Nezumi serves as the base commander and is the unit's defining figure, a greedy officer whose schemes drive its appearances. A trio of non-canon subordinates named Gucci, Noiri, and Goshima also appear in supplementary material. In a non-canon anime moment following the Marineford conflict, the branch's Marines are shown celebrating the defeat of the Whitebeard Pirates.