Zaku Abumi

was a shinobi from Otogakure and a member of Team Dosu, which took part in the Chūnin Exams under covert orders from Orochimaru.

Background
In the anime, growing up as an orphan that lived on the streets and stole for a living, he was beaten for it. When Orochimaru found him, he told Zaku that he saw potential in him and offered to help him develop it in exchange for his loyalty, which Zaku accepted. Sometime later Zaku was seen singlehandedly fighting and defeating several Takigakure shinobi. From that day forward he refused to give up, even at the cost of his own life, not knowing that Orochimaru only took him in as a disposable pawn, a fact that his teammate started to suspect at the Chūnin Exams.

Personality
Like his teammates, Zaku was overconfident about his powers, especially the ones coming from his arms, as noted by Sasuke Uchiha and the fact he went into elaborate detail about his abilities. As such, he believed no one could beat him, and had a strong desire to win; however, he managed to be unaware of the enemies' plan until it was too late, as seen with his last opponent Shino Aburame. Zaku also had a tendency to say whatever he wanted without regarding the consequences, as he called Chōji Akimichi fat, and then had a difficult time blocking the enraged genin, and then told Sasuke that he is the one who injured Sakura Haruno, leading to the crippling of his arms. He was seen to have some sense of care for his teammates, as when Dosu was plummeting to the ground from Lee's attack, Zaku was seen using his air waves on the ground to soften the blow, though he showed no such concern for Kin, being fully willing to kill her when Ino Yamanaka took her hostage. He was also described as loyal, and a show-off.

Appearance
Zaku had spiky, black hair and dark eyes. He wore a beige shirt with two black stripes and three prints of the kanji for down the front. His forehead protector had an attached happuri under the cloth rather than connected to the metal plate, resembling Yamato's. As with his teammates Dosu and Kin, he wore a snake-patterned scarf around his neck.

Body Modifications
Zaku, like many ninja from Otogakure, had been physically altered with unnatural enhancements that improved his abilities; in his case, he was fitted with hollow air tubes that extended through his arms and opened through his hands, allowing him to propel a combination of air pressure and sound in various ratios, controlled by his chakra. In his fight against Shino, Zaku claimed to be able to control the sound more precisely than simply firing it in one direction, but this was never shown. A proven downside of Zaku's ability was, that should the air tubes be clogged, it would result in a terrible backfire, as the air cannot escape out, instead they would burst out of the side of his arms, causing great backlash damage, to the point of having his arms being destroyed inside out.

Chūnin Exams
Team Dosu travelled to Konohagakure to participate in the Chūnin Exams with the secret goal of killing Sasuke Uchiha. Before the exam started, Zaku and his teammates overheard Kabuto Yakushi talking about their village and decided to attack him. After Zaku threw Kunai as a distraction, Dosu attacked Kabuto and damaged his hearing. To prevent the situation from escalating, the exam proctors, led by Ibiki Morino, appeared and settle things down. After Zaku passed the written portion of the Chūnin Exams, he moved onto the second phase alongside his teammates.

During the second phase of the exam, Dosu initiated the team's real mission of killing Sasuke. After several days in the Forest of Death, Team Dosu finds Sakura alongside her injured teammates. Seeing an open opportunity to kill Sasuke, Team Dosu attacks Sakura, activating her traps she had hidden in the process. After getting past the traps, Team Dosu was intercepted by Rock Lee. As Dosu got caught in Lee's Front Lotus, Zaku emitted air into the ground to soften his landing. Surviving the attack, Dosu resumed his fight and defeated Lee. With Lee out of the way, Kin captures Sakura, leading her to cut off her long hair to get free of Kin's grip and fight back. After numerous times attempting to attack Zaku, Sakura manages to finally injure him. Zaku immediately retaliated by punching her repeatedly, causing her to bleed. Observing the situation from afar, Team 10 arrives and intervenes. Because Chōji audibly pleaded his desire to leave and not fight, unlike his other two teammates, Zaku was willing to let Chōji go though angered him into a fight by insulting his weight. Zaku fought against his Chōji's Human Bullet Tank technique which overpowered his own jutsu. As Ino gained control of Kin's body, she demanded Team Dosu to hand over their scroll, using their teammates body as leverage. Zaku promptly attacked her, hurting both kunoichi in the process. After Zaku and Dosu began insulting Konohagakure, Neji and Tenten appeared and interrupted them.

After Sasuke recovered and activated his curse mark, he noticed Sakura was injured, which Zaku proudly took credit for, prompting Sasuke to enter the fight. Getting fed up with the battle dragging on, Zaku attacked with his most powerful technique in attempt to kill all of Team 7. Surviving the attack and rescuing both his teammates, Sasuke attacked and injured Zaku with shuriken. Distracted, Sasuke swiftly appeared behind Zaku and dislocated his arms, knocking him out in the process. Unable to bring himself to face Sasuke, Dosu handed his team's scroll over to Team 7 and retreated with his teammates. After Zaku and his team recovered, they manage to get both scrolls needed to proceed into the finals and manage to pass the second phase of the test.

After deciding to participate in the third stage preliminaries, Team Dosu reunited with Orochimaru, who was disguised as their Otogakure sensei. Throughout the beginning of the preliminaries, Zaku acted out that both his arms were still dislocated, even towards his own teammates. After watching Sasuke's fight, he was matched against Shino Aburame. Because Zaku's arm was in a sling from his encounter with Sasuke, Shino advised him to forfeit the match. Zaku refused, and instead attacked Shino with his one good arm. In attacking, Shino was given an opportunity to box in Zaku with bugs, forcing Zaku to choose between attacking him or attacking the bugs, leaving the other to attack Zaku from behind. Zaku chose to attack both, and pulled his other arm out of its sling. As Zaku prepared to blast the two opposing forces, his arms detonated, making them unusable and putting him in serious pain (in the manga, his right hand was even blown off of his body. In the anime, his arms were severely damaged but still attached to his torso). As Zaku writhed, Shino revealed that the tubes in Zaku's arms had been filled with his bugs, causing the pressure of Zaku's attack to go inward when it couldn't escape. Shino then dealt a finishing blow, knocking him out, and medics came to move Zaku on a stretcher, with his severed arm lying on top of his chest.

Konoha Crush
As the Konoha Crush occurred, Orochimaru summoned the First and Second Hokage, leading to the Third to use the Dead Demon Consuming Seal to seal the deceased Hokage. After successfully sealing the two at the cost of his life, it was revealed that Zaku, along with Kin were used as sacrifices to summon the former Hokage souls.

Trivia

 * Like all members of his team, Zaku's name is a sound word, specifically that of a stab, but also of chatter. "Abumi" comes from, the Japanese name of the stirrup.
 * Like many of the other characters, Zaku appeared in the omake at the end of Naruto: Shippūden episode 129, along with the rest of Team Dosu.
 * Zaku had a tendency to end his sentences with "hm", just like Deidara.

Quotes

 * (To Kabuto)
 * (To Shino)