Den

Broad and muscular, Den lets his fair, curly hair fall well past his shoulders. His nose is long and hooked, angling downward above a mustache and a dark, sharply pointed goatee, and a grin sits on his face in almost every scene. Each of his arms bears a tattoo shaped like a four-leaf clover, the same emblem printed on his short-sleeved shirt. He tops his head with a broad-brimmed hat and wears what look like safety goggles, with an earring in each ear and beads strung around his neck. Like his brother Tom, he keeps a tool bag belted at his waist, a cloth resembling an apron tied just below it. One feature sets him apart from most merfolk: his hands are webbed, a trait usually seen in Fish-Men.

Warm and good-natured, Den wears a smile through nearly every scene and gives off an openly friendly air. He shares a speech quirk with his older brother Tom, peppering his words with the expression don.

Following in Tom's footsteps as a shipwright, Den has a discerning eye for fine craftsmanship and could tell the Thousand Sunny had been built from the rare Treasure Wood Adam. His work studying the Sea Forest gives him familiarity with the area. When it comes to coating, his skill is formidable: the immense Thousand Sunny, a job that ordinarily stretches across several days, he finished on his own in a short span.

Out in the Sea Forest, Den met Franky, took on the coating of the Thousand Sunny, and explained he had learned of both Franky and Iceburg through Kokoro's letters. He described to Franky how the genetics of Fish-Men and merfolk play out in interspecies breeding, and pointed out that Jinbe, once again a wanted criminal, was lingering in the forest because the island was closed to him. After Luffy, Shirahoshi, Sanji, Hatchan, and Chopper reached the Sea Forest, Den stayed there with Hatchan and Camie while the Straw Hats fought the New Fish-Man Pirates, remarking on the odd departure of the island's whales. Once the battle concluded, the three were astonished to watch Sea Kings tow Noah into the Sea Forest.