Gōzu

and his brother Meizu are twin brothers and former Kirigakure Chūnin.

Background
They fled the village with Zabuza Momochi when he failed in his attempt to kill the Mizukage, and thereafter began working for him as assassins.

Abilities
Gōzu and Meizu are a paragon of coordination attacking. His large metal gauntlets house a retractable shuriken chain running between the two of them, which they can use to bind an enemy and then slice them to pieces. In the event that the shuriken chain is neutralized, Gōzu also has a release mechanism to free him from Meizu for individual attacks. He uses the sharp, poisoned claws on his gauntlets to shred his foes.

Land of Waves Arc
At the start of the series Zabuza sends them to kill Tazuna, but they are stopped by Kakashi Hatake, Tazuna's bodyguard. He ties them to a tree so that they can later be taken into custody.