Boo

Boo keeps his long orange hair in two ponytails, one trailing behind on the right and another falling across the left of his face. His eyes look shadowed and several front teeth are gone. He wears purple and black vertically striped trousers with a pale belt, a dark-green paludamentum fastened by a chain, and on his right side a dark glove plus light-colored armor pieces topped by a skull-marked pauldron. A flaming, fanged-skull tattoo marks his left arm, and three double-bladed axes ride on his back.

Once Sugar's power turned him into a toy, he took the form of a wind-up jester with a key in his back.

Boo carries himself calmly and keeps his composure, restraining his brother Sai when the latter erupted at Luffy and even apologizing on his behalf. He held back his own grandfather from striking Luffy before their bout. Sai considers him something of a slacker who neglects his training, and he tends to play the level-headed foil to his emotional sibling. Even so, he can be cutting, taunting Kelly Funk as a midget despite knowing the insult stung.

Holding the second-in-command rank of the Happo Navy implies real strength, likely surpassed only by Sai, and he endures the dangers of the New World. He practices Hasshoken, a style that channels destructive vibrations through strikes, and he wields Armament Haki, coating his axes to hit harder. His stamina is notable, since he bounced back from a beating by the Funk Brothers without treatment, though his Haki still failed to pierce Bobby Funk's hardened body.

In the Dressrosa Arc, Boo entered the C Block battle royale alongside Chinjao and Sai, partly to disrupt the Donquixote Family's weapons trade. He crushed weaker fighters but fell to the merged Funk Brothers, was later turned into a toy, then freed when Sugar collapsed. He joined Luffy's coalition against Doflamingo, battled through Pica and the Donquixote officers including Machvise, and after the victory saw the Happo Navy pledge itself to the Straw Hat Grand Fleet before parting ways. He afterward attended Sai and Baby 5's wedding.