Dosu Kinuta

is the unofficial leader of the three Genin (Kin Tsuchi, Zaku Abumi, and himself) from Otogakure who entered the Chunin exams in order to get close to and assassinate Sasuke Uchiha under Orochimaru's orders. Orochimaru secretly only uses the trio to test Sasuke's ability, and ends up using Dosu's teammates for sacrifices during the Invasion of Konoha.

Personality
Dosu seemed very loyal to Orochimaru's cause, and to a lesser degree, his teammates. Though he says himself sound ninja are willing to sacrifice their own team mates to the cause, he promises to avenge Zaku after his debilitating defeat at Shino Aburame's hands, and seems to have had confidence in Kin before her match with Shikamaru. He showed dedication to Orochimaru's task at first (sacrificing Kin would have disqualified the team from the official exams, pointing towards his main task being the assassination of Sasuke) but perhaps became disillusioned with his sensei after he sees that he has given Sasuke a cursed Seal.

It is unknown whether he planned to stop following Orochimaru, or whether he simply wanted to prove himself better than Sasuke for Orochimaru's purposes, but following the preliminaries he attempts to kill Gaara to get to fight Sasuke earlier in the finals. Dosu, however, seeing only Gaara's fight with Rock Lee was oblivious to the former Shukaku, which easily killed him in one blow.

It is also very possible that Dosu is sexist, as he swore to avenge Zaku upon his defeat by Shino, but was going to kill Kin without a second thought, just to get to Ino while she took control of her body.

Chunin Exam
In the Chunin exam arc he passes the written test by interpreting the sound of other's pencil markings. In the forest of death he and his team fight Sakura, Rock Lee, and Team Asuma. The battle is eventually intruded on by Lee's teammates and then by an awakened Sasuke Uchiha. Due to the latter, Dosu surrenders his scroll and flees, carrying his incapacitated team. He easily defeats Choji Akimichi in the last match of the exam preliminaries, but is killed by Gaara in the month between the preliminaries and the finals.

Abilities
His main attacks came from his ability to manipulate sound, with help from the metal sound amplifier, the "Melody Arm" on his right forearm, which he used to generate sound for these attacks. His abilities attack the inner ear, directing his sound deep into it, which would cause great pain, disorientation, and nausea. During their match, Choji attempted to block his attacks by pulling his head inside his Human Bullet Tank, only to be thwarted by the fact that by directing sound through the water in his body (Choji, having accidentally crashed into a wall at this point, allowing Dosu to hit him at extreme close range) Dosu could still generate the effect. Choji was instantly defeated by the attack.