Gōzu

along with his twin brother Meizu were chūnin-level shinobi of Kirigakure before defecting and becoming mercenaries alongside Zabuza Momochi.

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

Personality
In sharp contrast to his brother, Gōzu is described as being rational, level-headed and calm.

Appearance
Gōzu had shoulder-length, wild dark-brown hair and dark eyes. He wears a rebreather that covers the lower half of his face and a large, clawed, poisonous gauntlet on his right arm which had a chain coming out of it that had the other end attached to his brother's own gauntlet. He wore a camouflage suit with bandages around his waist, dark-coloured, knee-length sandals and a ragged black cape. His Kirigakure forehead protector had a single horn on it.

Abilities
Gōzu and Meizu are a paragon of coordination attacking. Gōzu's 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 neutralised, Gōzu also has a release mechanism to free him from Meizu for individual attacks. He uses the sharp, poisoned claws on his gauntlet to shred his foes.

Nature Transformation
Gōzu and Meizu have proven profficient in Water Release being capable of appearing out of puddles, hiding in them when needed.

Land of Waves Arc
At the start of the series Zabuza sends them to kill Tazuna. Using the Water Release: Hiding in Water Technique to surprise Team Kakashi. With Gōzu immediately launching his brother in front of him the pair are seemingly able to kill Kakashi with ease. As they move on to attack Naruto Uzumaki, they are stopped by Sasuke Uchiha who breaks the chain connecting the two brothers. Still intent on killing them, the brother separate and attack the team. They are however stopped by Kakashi Hatake, and it is revealed that he had used the Body Replacement Technique to escape their first attack. He later ties them to a tree so that they can be taken into custody.

Trivia

 * According to the databook(s):
 * Gōzu has completed 313 official missions in total: 71 D-rank, 196 C-rank, 45 B-rank, 1 A-rank, 0 S-rank.
 * In Japanese mythology Gōzu and Meizu are fearsome guardians of the Underworld known more commonly as "Ox-Head" and "Horse-Face".
 * Gōzu literally means "Cow Head".