Itachi Uchiha

In the anime, Itachi was assigned to 'Team Ro' under the command of Kakashi Hatake. While other members questioned the wisdom of letting one so young join Anbu, Kakashi quickly recognised Itachi's talents. For his first mission, he joined Kakashi in a two-man team to observe a potential alliance between Konoha and the Land of Woods, but was instructed to kill the shinobi of the Prajna Group if they betrayed Konoha for their scroll as a peace offering. Quickly, the group revealed their trick, to which Kakashi and Itachi swiftly killed them. Afterwards, Kakashi congratulated the itachi for his exceptional work. As Itachi commented on Kakashi's borrowed Sharingan, Kakashi merely said he sees it as a gift and a means to protect his comrades. Later, Itachi found inside the 'Naka Shrine' during a secret clan meeting a stone monument, reading shocking information through his Sharingan. During the next few years, Itachi continued to serve in the Anbu under the guidance of Kakashi. At some point in time in their childhood, Sasuke helped Itachi on one of his missions to capture a giant boar. Itachi told Sasuke to avoid his vital points. He then threw kunai with explosive tags around the boar, to confuse it and to give Sasuke an opportunity to shoot the boar. Sasuke, however, missed completely. After Sasuke apologised, Itachi advised him he needs to train more.

At age 13, he was promoted to the rank of Anbu captain. When the Uchiha clan began planning to overthrow Konoha, Itachi was tasked with exploiting his position to spy on the village. Knowing that a coup d'etat would only trigger the beginning of another ninja-world war, Itachi became a double agent, showin loyalty to the Uchiha while secretly passing on information about them to the Third Hokage and Konoha elders. Itachi's best friend and brother,Uchiha Shisui, opposed the coup d'etat as well, but after having his right eye stolen by Danzo for its powerful Genjutsu ability, Shisui realised that it was beyond his power to stop the Uchiha clan's impending doom. Meeting Itachi in secret on a cliff overlooking the Naka River, he entrusted his remaining eye to him, requesting that Itachi protect the clan's good name. The grief of losing his closest friend ultimately awakened Itachi's Mangekyo Sharingan, which he soon after used to read more of the secret stone monument.