Den

Den is Tom's younger brother. He is a bering wolf-fish merman. He is also a ship carpenter and Sea Forest researcher.

Appearence
Den is a muscular, slim merman with curly long hair. He wears a dark hat and a pair of glasses which look somewhat attached to his hat. He has two four-petaled clover tattoos on each of his arms. There is also a clover sign on his darkly colored shirt. He has two earrings on each of his ears and a necklace around his neck. He has a goatee and a pointy nose. Also he has a bag full of tools attached to his belt. Although he is the brother of Tom, they don't resemble each other.

Powers and Abilities
Den is a ship carpenter and as Tom's little brother it is very possible that he is as talented as Tom if not greater. Being a Sea Forest researcher, he has some knowledge about sea forests. He also appears to be skilled coating mechanic.

History
Den was first seen on the Thousand Sunny talking with Franky about Tom. Den compliments on the ship that Franky built and agreed to coat it. When Franky asked Den about why he doesn't look alike like Tom, Den explained to Franky about how fishman and merman genetics work when there is inter-species breeding. Fishmen and Merfolk still carry the genes of their ancestors, so the species is not determined only by the parents, but it can be one among all the species of the ancestors. Den then jokingly asked Franky if one of his ancestors is a robot. When Franky noticed someone sitting in front of a grave in the distance, Den pointed out that person is Jinbe, explaining that Jinbe is waiting for someone in the forest since he cannot enter the island.