Niseusopp

At a glance Niseusopp could pass for Usopp, the only obvious gap being a few wardrobe details. His fish-man heritage, however, tints him a bluish shade and equips him with the gills, the webbed hands, and the pointed teeth of his kind. The long, tapered nose he sports echoes Usopp's, and together these traits let him stand in convincingly for the Straw Hat Pirates' marksman.

Where the genuine Usopp hides behind nervous, manufactured swagger, Niseusopp is simply cocky and full of himself, his arrogance coming across as real rather than bluffed.

His fish-man blood likely granted him strength around ten times a human's, yet it counted for little: Roronoa Zoro brought him down with hardly any effort. He also brags about a cage in his possession, which he claims to have swiped from the Marines.

Together with Niseluffy and Nisezoro, he took up the pretense of being the Straw Hats. Backed by their Nisenise Pirates underlings, the three hit the 153rd Marine Branch, sent it scrambling, and bolted for Orange Town. They sacked that town too, harming its residents and wrecking buildings, then claimed a bar at its edge and pressed a local woman into doing their cooking and cleaning.

When Luffy and the Set Sail Pirates followed their trail to that bar, Luffy branded Niseluffy a counterfeit; the impostor flipped the accusation back, and Niseusopp sided with him. As the standoff turned to blows, Niseusopp dared the rivals to take it outdoors, griping that the bar was too cramped. After the underlings fell and a Gomu Gomu no Stamp from Luffy dropped Niseluffy, Niseusopp and Nisezoro tricked Luffy into the stolen Marine cage and began crowing about their triumph. Their victory talk collapsed when the true Roronoa Zoro showed up, beat Nisezoro, and finished Niseusopp off in the same exchange. Left flattened, he was handed to Nezumi once the officer arrived to make the arrests.