Ask a Naruto fan who their favorite character is, and chances are it'll be an Uchiha. One of the most tragic characters of the series, Itachi Uchiha, was a dedicated leaf shinobi. One of the most skilled ninjas of Konoha, Itachi joined the ANBU Black Ops at age 11. While at the ANBU, he was made to spy on his clan, members of which were planning a coup d'etat against the leadership in Konoha.
At age 13, Itachi was given a special mission that required him to kill every member of the Uchiha clan by Danzo Shimura. Declared a criminal and a rogue ninja, Itachi then went on to join the terrorist organization called "the Akatsuki." For most of the series, the Akatsuki members were on separate journeys to procure the jinchurikis of the tailed beasts. Since Itachi's target was Naruto, the two ran into each other more than once. In their last interaction, fans saw a peculiar moment, where a crow came out of Naruto's mouth and put Itachi under a genjutsu.
Fans have often wondered what caused this incident and what Itachi did to get this outcome. Let's take a look.
Throughout the years, the Uchiha clan has been revered but also feared for their visual prowess and the Sharingan's power. The evolutionary stage of the Sharingan, called the Mangekyou Sharingan, is one of the strongest doujutsu's to exist in the Naruto-verse. To awaken the Mangekyou, an Uchiha must feel pain equivalent to losing the one you love and adore. For Itachi, this was his best friend, Shisui Uchiha.
Shisui was one of the few people able to awaken the Mangekyou Sharingan. His Mangekyou gave him access to Kotoamatsukami in each eye. The special power of the Kotoamatsukami allows the user to enter the mind of any individual within his field of view by manipulating them into believing false experiences seamlessly and completely, acting upon them as if they were truly acting on their own free will. It has often been regarded as a unique genjutsu of the highest caliber.
Shisui Uchiha, who shared the same ideals about peace as Itachi, thought of him as his brother. When the Uchiha Clan decided to enact their coup, Shisui sought to use the powers of the Kotoamatsukami to stop them. However, since Danzo Shimura stole one of Shisui's eyes, the task was almost impossible. Adamant on maintaining peace, Shisui gave his remaining eye to Itachi and died, entrusting him with his will.
In episode 126 of Naruto: Shippuden, Naruto encounters Itachi for the third time. Meanwhile, Sasuke and his team Taka are also moving to Itachi's hideout, so the former can kill him. On the other hand, several Konoha shinobi were also on a mission to find and kill Itachi. Since Itachi knew his death was near, he wanted to make sure he secured Sasuke's future one last time.
Before Itachi died, he wanted to talk to Naruto, presumably because he was still worried about what Sasuke would do after his death. However, Naruto was extremely angered upon seeing Itachi and was unwilling to listen to anything he had to say. Seeing no other option, Itachi was forced to cast a genjutsu to make him listen. After their conversation, Itachi realized that Naruto was determined to save Sasuke at any cost.
Thus as a last dying act, Itachi decided to give Naruto Shisui's eye, which would help him in case he needed to use force to bring Sasuke back to Konoha in the future. The eye replaced the original eye of Itachi's crow and was set to cast a genjutsu as soon as it encountered Itachi's Mangekyou Sharingan. This was because Itachi knew that once Sasuke killed him, he would have to implant the former's eyes to avoid complete blindness.
Itachi and several other shinobi during the War arc were brought back to life because of Kabuto's Edo Tensei. When a reanimated Itachi ran into Naruto for the last time, the former was forced to fight under the Edo Tensei's power. However, when Itachi used his Sharingan, the crow he put inside Naruto reacted to his eye and immediately put him under a genjutsu commanding him to "protect Konoha." Since Itachi was placed under a new and powerful genjutsu, his Edo Tensei link was broken, and Kabuto could no longer control him.
This ultimately leads to Itachi defeating Kabuto and releasing the Edo Tensei all over, making him one of the Fourth Shinobi's War's greatest heroes.
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