Genzou

ゲンゾウ

The sheriff and mayor of Cocoyashi Village (known as Coco Village in the 4Kids version), which is Nami's hometown. He serves as a father figure to Nami and Nojiko, having known them since childhood, and was quite familiar with their adoptive mother, Bellemere. He also held the town together after Arlong took over the island, ensuring everyone remained safe and able to pay their taxes.
Genzo wears a pinwheel on his hat because he used it to make baby Nami laugh (this pinwheel also inspired an attack for Luffy during their fight with Arlong). He played a role in rescuing Luffy after Arlong threw him into the ocean. All of Genzo's scars come from his first encounter with Arlong; when he tried to stop Arlong from taking Nami, Arlong ordered Kuroobi to cut every part of his body with a sword. He was also nearly killed by Arlong for hoarding novelty swords, until Usopp saved him.
Genzo's pinwheel inspired Nami's new tattoo—a pinwheel to represent him and a tangerine to represent Bellemere. After Nami sails off with Luffy and the crew, Genzo says he no longer needs his pinwheel and places it by Bellemere's grave. The origin of the pinwheel is then revealed. Bellemere said that Nami cried when she saw Genzo because he looked scary, but then Genzo put on his pinwheel to make Nami laugh. It is revealed later in the manga that Luffy is very interested in the pinwheel {this inspires a new attack for Luffy, Gomu Gomu No Pinwheel}, not even noticing the Navy who are trying to find Nami, only Genzo's pinwheel. However, this could be a put-down in reference to Luffy's simple-mindedness. He threatens Luffy that if he finds out that he made Nami cry, he'll come after him. However, Luffy lived up to that promise, as Nami's sister, Nojiko, pointed out.
Genzo appears again later and is outraged by Nami's wanted poster, wherein she is in a bikini, saying she'll get more suitors than bounty hunters, yet he has blown it up poster-sized and hanging in his house.