Usamen has a prominent underbite, irregular eyes, cleft chin, and a Japanese sushi chef headband. His cleft chin was replaced with a more squared jaw in later chapters. Usamen also wears a piece of fabric or apron, hanging from his hip, that features the kanji 鮮 (which generally means "fresh").
Dark Continent Expedition arc
Usamen debuts as one of the the ten people affiliated with Beyond Netero to join him on the adventure to the Dark Continent. When Ging talks with Pariston, Usamen quickly moves to accost him, but is effortlessly lifted by Ging and subjected to several punches. Though all of those were feints, Usamen thought he had actually been hit by those punches until he realized otherwise. Being confronted by Mascher and Marione, Ging then offers to pay double of what Beyond has offered them all in order to become the 2nd in command, Usamen accepts Ging as 2nd in command, but will refuse to follow any of his commands and refuses to accept any of his money.
The Dark Continent Expedition Team has divided into 2 groups, one that will accept Ging's money and the others that won't, which Usamen was a part of. Ging, however, baffles them all with his deduction that they're all specialists in various fields with skills necessary for them to get to and survive within the Dark Continent.
Later, Ging demonstrates his abilities in the game of Pip-Play. Usamen, a self-proclaimed master of Pip-Play, looked as though he was about to faint from being unable to measure up. Ging admits that the game has no practical use, but Usamen lividly states that's what makes Pip-Play so amazing. After Muherr and his men return from the Hunter Exam and try and pick a fight with Ging, Usamen surprisingly defends Ging, by trying to reason with Muherr and his men.
Abilities & Powers
Usamen's specific Nen abilities are not revealed, though Ging deduces that he is a specialist in some field; his abilities, or at least one of them, must have been scouted to be able to deal with the dangers of the Dark Continent.
Usamen is a self-proclaimed master in the game of Pip-Play, in which a player moves around his aura to do tricks, though that game has nothing to do with one's actual abilities, being no different than spinning a pen on one's fingers. However, he was still no match for Ging's abilities. Since creating shapes with one's aura is considered a Transmutation ability, Usamen might be skilled in this field.