Zaku Abumi was part of the Sound ninja team recruited by Orochimaru to test the power of Sasuke Uchiha, under the false guise of assassinating him.
Zaku was a dirt-poor street orphan who was forced to steal to survive. One day, Orochimaru saw him. Noticing that there was potential in the boy, he recruited him into the Sound Village and operated on his arms. As a result, Zaku obtained wind tubes in his arms that he could use to fire airwaves at his opponents. He was shown to be capable of taking on several other ninja as practice.
Zaku was part of the Sound genin team sent to test Sasuke Uchiha alongside Dosu Kinuta and Kin Tsuchi. The three of them ambushed Team 7 in the Forest of Death, where Zaku displayed his prowess with his air tubes by attacking Sakura. He then argued with Rock Lee, saying that hard work is worthless, and that one needed some kind of outside force or modification to become stronger. He then described himself as an example of the results of said modifications, and proceeded to attack Lee. However, he and the team were disrupted by Team Asuma and later the Cursed Seal-powered Sasuke, who broke both of his arms.
In the Exam tournament, Zaku was set up against Shino Aburame. Shino urged him to quit due to his broken arms, but Zaku insisted to fight - he still had one functional arm. He hit Shino with a blast of air, but was unaware of the horde of bugs that were behind him. Shino urged Zaku to forfeit again, for his technique could only be used in one direction; thus, if he attacked either Shino or the horde of bugs, the other would attack him. Zaku then turned the tables on Shino, revealing that both arms were functional. He fired his Decapitating Waves again out of both hands; however, Shino had prepared for this, and he had stuck bugs up the tubes. With nowhere to go, the pressure in the tubes ripped Zaku's arms apart. (In the manga, one of his arms goes flying off, but in the anime it is less severe)
He is not seen again until Orochimaru uses him as a human sacrifice to reincarnate the 2nd Hokage.
Zaku had messy black hair and a face guard similar to that of the 2nd Hokage.
Zaku was overconfident and cocky, and he was very impulsive. He enjoyed taunting his opponents and toying with them as well, and he wouldn't back down from a fight. He put a lot of faith in Orochimaru, and saw him as a father figure. In his eyes, he was indebted to Orochimaru because the latter had made him powerful (Ironically, while he was explaining this to Shino, Orochimaru was talking to Kakashi about how Zaku, Dosu, and Kin were expendable pawns and that he didn't really care for them)
Powers and Abilities
Zaku's Decapitating Airwaves were his main ability; he could fire blasts of sound-powered air from the tubes in his arms. These blasts were quite powerful, and could rip through trees and pretty much anything.