Rinji

was a shinobi from Otogakure and a member of Team Guren. He also was an underling of Orochimaru.

Personality
Rinji had a laid back attitude and was rarely worked up about anything. At the same time, he was shown to have sharp intellect and was a planning type. He was also somewhat ambitious, as he wanted to report to Orochimaru in Kabuto's place, threatening Kabuto's position as Orochimaru's right-hand man, which led to Rinji's death.

Abilities
Rinji was a bat-user; he had the ability to manipulate bats via the method Bat Controlling, and use them to create ultrasonic waves so that he could communicate with bats, allowing him to survey the surroundings and give battle instructions to his subordinates. He also appeared to have a sonar-like power of his own that allows him to detect sound from a large radius. By using sound his bats produce as a weapon, he can affect the opponent's mind and equilibrium, and also grants him immunity from Guren's Crystal Release techniques.

Three-Tails Arc
After the selection battle Kabuto Yakushi and Guren held in the hideout, Rinji became Guren's subordinate. When Guren returned, she orders him and the rest of his team to dispose of Team 8. During which the fight he took on the role of leader and presumably used his sonar powers to allow his team to fight in Kigiri's Smokescreen Technique. After feeling that he analyzed his opponent's skills enough, he was ready to finish them, until he detected Shino Aburame's insects coming. Feeling the increased danger, he ordered his men to retreat.

Later, Rinji and the rest of the team came to Guren's aid when her crystal barrier was destroyed by Naruto and Gamatatsu. After retreating, the team, minus Gozu, was ordered to stop Team 8 from pursuing them. Rinji used his bats to try and catch the Konoha ninja by surprise, but Hinata Hyūga's Byakugan nullified his efforts. The battle was interrupted by the actions of the Three-Tails and Rinji and his team had no choice, but to fall back again.

After meeting up with Kabuto again, it was then revealed that Rinji was a spy for Orochimaru who was ordered to keep an eye on Guren. It was also revealed that he had spent years acting as spy, inserting himself into villages and even as a fellow prisoner in Orochimaru's dungeon. When talking to Gozu, he claimed his actions were to aid his sickly sister from a far off village. When they were once again sent to stop Team 8, Rinji did not participate, allowing his team-mates to be defeated by Team Two. Instead, he noticed the attempted sealing of the Three-Tails. When he was unable to stop it by himself, he had Guren come help him and they ultimately proved successful.

Rinji continued to show a number of uncharacteristic behavior after that, but this was later revealed to be Kabuto disguised as Rinji; Kabuto revealed that he killed the real Rinji. When Guren planned to run away with Yūkimaru, Kabuto summoned the real Rinji using Dead Soul Technique, who fought with Guren. His bats' ultrasonic waves were shown to break Guren's Crystal Release, making the Crystal Release useless against Rinji. To protect Yūkimaru, Guren crystallized herself, along with Rinji, which caused them to fall into the lake. Guren was later saved by Gozu.

Trivia

 * Despite Rinji's troubled relation with Kabuto, they ironically shared one trait: they both had spent many years acting as spies and had a knack for appearing genuinely cheerful and kind-hearted to strangers to better deceive them.
 * Rinji was shown fighting Sakura in the fourth opening, but this never occured, as he was killed by Kabuto before anything happened.