Dosu Kinuta

Age: 14 (I)
Birthday: June 12
Blood type: A
Height: 156 cm (I)
Weight: 48 kg (I)

Dosu is a genin from the Sound Village, and leader of his squad. They were under the direct supervision of Orochimaru during the chunin exams. Dosu uses a sound amplifying device on his left arm, called a melody arm, to increase the vibrations he makes when he hits something, causing damage to the opponents ears and messes up their sense of balance. He is the only member of his squad to advance to the second stage in the chunin exams after defeating Choji Akimichi.
He showed dedication to Orochimaru's task of killing Sasuke Uchiha, but later became disillusioned after learning that Orochimaru had given Sasuke a cursed seal. Realising that he and his team were actually pawns used to determine Sasuke's worth, Dosu's outlook changed as he lost any and all loyalty towards Orochimaru and vowed to kill Sasuke for the purpose of undermining Orochimaru. Because of this, he would attempt to take down Gaara prior to the actual match to lessen the obstacles beforehand, a rather rash decision that cost Dosu his life.

(Source: Naruto Wikia)