Zaku Abumi was a Genin-level ninja from Otogakure. He was part of the team that took the Chunin exam in order to assassinate Sasuke Uchiha. Like many Sound ninja, he has been physically altered with unnatural enhancements that enhance his abilities; in his case, he was fitted with hollow air tubes that extend through his arms and open through his hands, allowing him to propel a combination of air pressure and sound in various ratios, controlled by his chakra. He was an orphan living on the streets who hustled by stealing for a living, and was almost always beaten for it. Orochimaru had told him he had potential and liked the strength in his eyes. He refuses to give up, even at the cost of his own life.