Itachi Uchiha

was an ANBU captain from Konohagakure's famed Uchiha clan. He later murdered his entire clan in what would become known as the Uchiha clan massacre, and defected from the village becoming an S-rank missing-nin, and a prominent Akatsuki member who was partnered with Kisame Hoshigaki.

Background
Itachi was born into the Uchiha clan as the eldest son of Mikoto and Fugaku Uchiha, and was praised by all as the best of his generation, and a genius above all others, even by the standards of the battle-adept Uchiha clan, Itachi's prowess far outshone their own. However, few could understand him. When he was only four, Itachi had already witnessed countless lives lost due to the Third Shinobi World War, which emotionally traumatised him and turned him into a pacifist.

Itachi was a highly perceptive child, wise beyond his years and spent much of his time researching the history of the village from the writings their ancestors left behind. Because of this, Itachi was never limited to the view of his own clan but worried about the fate of the village as a whole.

During the Nine-Tails' attack on Konoha, Itachi was left alone to take care of his infant brother Sasuke and promised to protect him no matter what. In the anime, it was shown that during their childhood, Itachi made a game of collecting paw prints of cats with his brother. The last paw print to be collected was Nekomata's, who Itachi had defeated and asked him to fight Sasuke with all his might when Sasuke got older.

At age 7, Itachi graduated from the Academy at the top of his class after only one year, mastered the Sharingan at age 8, passed the Chūnin Exams at age 10, enrolled in ANBU half a year later and became captain by 13. 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 told him he needs to train more.

Itachi was praised highly by his father, who saw the family's future in Itachi and hence inadvertently neglected his younger son. However, during this time Itachi showed great affection towards his little brother and even encouraged his father to come to the Academy enrolment ceremony for Sasuke, something their father had otherwise forgotten, caught up an important mission that would establish Itachi a place in the ANBU ranks.

When the Uchiha clan began planning to overthrow Konoha, Itachi, as an ANBU, was tasked with spying on the village. Knowing that a coup d'état would only escalate to the beginning of another ninja-world war, Itachi began spying on the Uchiha instead, passing on information to the Third Hokage and Konoha elders. Though the Third Hokage ultimately decided to reason with the Uchiha in order to dissuade them from their actions, Danzō Shimura met secretly with Itachi Uchiha and inveigled him into choosing the lives of his clansmen or that of his little brother. During this time he began to act strangely, not attending the clan meetings, speaking out against the clan, and becoming the prime suspect for the murder of his best friend Shisui Uchiha, who was drowned in the Naka River. In reality, Shisui died after he entrusted his left eye to Itachi, the other having been taken by Danzō. Due to this the clan lost hope in Itachi, and his father began shifting his focus to Sasuke instead. Meanwhile, the Third's attempts to negotiate a bloodless end to hostilities between the two parties were proving ineffective, so against Hiruzen's wishes, Danzō Shimura and the Konoha Council ordered Itachi to wipe out the Uchiha clan.

Before the fateful night arrived, Itachi discovered the existence of Tobi — under the guise of a vengeful Madara Uchiha — who was attempting to rekindle the flames of war in Konoha. In return for not attacking Konoha, Itachi offered to help him claim vengeance against the Uchiha for turning their backs on him decades earlier to which Tobi agreed. Itachi slaughtered his entire clan overnight, including his friends, superiors, family, and lover; prior to killing his parents, the two people whom he was most hesitant to kill, they stated that they were still proud of their eldest son, and requested that he took care of Sasuke before allowing a tearful Itachi to kill them. When Sasuke returned late from a training session, Itachi spared Sasuke because he loved his little brother, and as per the agreement between him and Danzō, did not want to take the life of the person most important to him. He lied to his brother, making himself out as a villain who had killed their innocent family only to test his capacity, and told Sasuke he was not even worth killing. In addition, Itachi told him, "You've always wanted to surpass me. That's why I'm going to let you live… if you wish to kill me, then hate me, despise me… and by all means flee, cling to your wretched life". Itachi also revealed to Sasuke the secret meeting place of the Uchiha, where Sasuke can learn the true history and purpose of the Sharingan. Itachi told him that in order to awaken the Mangekyō Sharingan, Sasuke had to kill the person closest to him, and that when they met again, they should have the same eyes.

Sasuke managed to stand back up, awaken his Sharingan, and pursue Itachi. Upon reaching Itachi, he managed to knock off his forehead protector. Itachi shed a tear as he was picking up his forehead protector, then proceeded to incapacitate Sasuke, who awoke in the hospital, only remembering up to Itachi's speech. By doing all this, Itachi hoped Sasuke would take vengeance on him and become a hero to Konoha, thus redeeming the Uchiha name. Hoping that his little brother would someday be powerful enough to kill him, Itachi left the village as a traitor. Knowing that Konoha would still want to eliminate Sasuke, Itachi pleaded with the Third Hokage to keep Sasuke safe and threatened Danzō not to harm Sasuke or else he would reveal everything he knew about Konoha's secrets to enemy nations.

Itachi joined Akatsuki in order to keep an eye on the organisation, along with Tobi, in case either ever acted against Konoha, all the while planning for his death at Sasuke's hands. During his time in Akatsuki, Orochimaru tried to steal his body to gain the Sharingan, but Itachi trapped him in a genjutsu and severed his left hand. Itachi was further partnered with Kisame Hoshigaki, who initially tried to intimidate him. However, they eventually became good partners. Sometime after Orochimaru fled, Itachi helped recruit Deidara by beating him in battle using only genjutsu, to which Deidara swore vengeance.

At some point in time, Itachi contracted a fatal disease. He kept himself alive through the intake of various medicines, and sheer "willpower", in the hopes of living long enough to die by Sasuke's hands.

Personality
Ever since his first appearance, Itachi had always been inscrutable. Unlike the vast majority of his clan, Itachi was not interested in personal gain, caring more for his village as a whole. Flashbacks showed that he used to be a compassionate brother, but his initial appearances depicted him as an Akatsuki criminal interested in the organisation's success and secrecy before all else. Later his interest in Akatsuki was revealed to be an act, and his true intentions for joining the organisation were to spy on it from within. Nonetheless, Itachi and his partner, Kisame, cooperated better than most Akatsuki partners, and despite the differences in personalities, appeared to have mutual respect for one another.

While a disgraced man who has lost all he holds dear, Itachi remained a dutiful and selfless individual, caring only for both his village and little brother's well-being; having never fallen victim to his clan's inherited Curse of Hatred that would normally follow the awakening of the Sharingan. Itachi possessed incredible control of his emotions, only showing surprise when opponents proved more powerful than expected, and even then did not lose his composure. After his death, he has been shown to have a sense of humour, such as questioning Naruto's claim that no one could survive Nagato's attack when Naruto clearly did, and calling his younger brother a "snake expert" while fighting Kabuto Yakushi.

Itachi was shown to be highly intelligent, something even Tobi acknowledged. From a young age, Itachi was very astute with a great respect for the past and his personal history. From this, by the age of seven, his wisdom and understanding of the world was on par with the Hokage, as noted by Hiruzen Sarutobi. He was quick-witted, observant, and intuitive; rarely being caught off guard or deceived. Itachi had great foresight; his foreknowledge of Sasuke's victory against Deidara, his own pre-meditated death by Sasuke's hand, and the implantation of the Kotoamatsukami-imbued crow inside Naruto were some examples seen.

However, while Itachi was a powerful shinobi, he was not arrogant, and complimented his opponents at times on their abilities. After his death, Itachi realised that he should not have tried to deal with Sasuke on his own and encouraged Naruto to never forget his friends. Likewise, Itachi took no enjoyment in violence or combat, instead preferring to avoid battle or, if not possible, end it as quickly as he could.

As Kabuto noted, Itachi lived in deception. On top of his pretence in promoting Akatsuki's goals, he also pretended to seek the Eternal Mangekyō Sharingan. During a genjutsu fight with Sasuke, he claimed to have only let Sasuke live to take his eyes, and that the Uchiha clan had been tainted and corrupt, since clan members would kill their friends to obtain the Mangekyō Sharingan and transplant another Uchiha clan members' eyes to make the power permanent. Once the genjutsu was released, he called it his true self, implying his emotionless personality was also a façade. This persona was later revealed to be an act to ensure that he would die by Sasuke's hands. After learning Sasuke refused to go back to Konoha post-mortem, Itachi placed all his faith in Naruto, who he noted had inherited Shisui's will and was determined to save Sasuke. Despite all his treacherous actions, Itachi only did them all to protect Sasuke and Konoha. Finally, even while knowing the dark sides of the village, he still considered himself a shinobi of Konoha. Along with Sasuke, Itachi also dearly loved his parents, Fugaku and Mikoto Uchiha, even though he disagreed with their plans. When he was forced to kill them, having put them off for last, Itachi wept and shook violently as he committed the act.

Appearance
Despite his status as an infamous shinobi, Itachi's appearance was not the most intimidating, apart from the intensity of his gaze. While living in Konoha, he would regularly have a gentle look in his eyes, especially directed towards his younger brother. After joining Akatsuki, they would regularly have a stern look to them.

Itachi was a young man with onyx eyes, black hair with bangs that framed his face, and a low-tied ponytail which reached down into his upper back. The ponytail was, however, later obscured by the high collar of the Akatsuki cloak he wore after joining the organisation. Itachi's most distinguishing features were the long, pronounced tear-troughs under his eyes. Itachi and Sasuke also bear slight similarities to one another in terms of their appearance as Naruto nearly mistook Itachi for Sasuke when they first met, while Tobi and Kisame commented upon their resemblance when they first encountered Sasuke.

When he lived in Konoha, his casual clothes consisted of a black shirt with the Uchiha clan symbol on the back, and pants with a weapons pouch strapped to his back. When on duty, he would wear the standard ANBU uniform complete with arm guards, a flak jacket, and a porcelain mask which was fashioned to resemble a weasel with a dark, triangular marking on top. As a member of Akatsuki, he wore a slashed Konoha forehead protector and the standard Akatsuki cloak. Sometimes, he would unbutton his cloak to mid-chest and rest his left arm there, rather than in the sleeve. After his cloak was incinerated by Sasuke's Kirin during their fight in Part II, it was revealed that he wore similar clothes to that of the rest of Akatsuki. His attire consisted of a body mesh under a blue v-neck T-shirt with a sash around the waist, and blue pants. Like most members of Akatsuki, he wore the forehead protector of his home village with a horizontal line gouged through it to symbolise his broken ties with the village. On his right ring finger was his Akatsuki ring, which was red and bore the kanji for. He also wore purple nail polish on his fingers and toes and a necklace which had three metal rings.

After being reincarnated, Itachi's eyes appear to have black sclerae like the other shinobi that Kabuto Yakushi reincarnated. He is also clad in a dark-red cloak.

Abilities
A child whose genius manifested at a young age, Itachi's teachers at the Academy noted that his progress hardly required any help, having been quickly promoted through the ninja ranks while still a child, further showing his remarkable capacities. In his battles, Itachi was shown to be an immensely powerful ninja and gained praise from allies and foes alike. During his battle against Kakashi Hatake, Kurenai Yūhi, and Asuma Sarutobi, Kakashi commented that Itachi was not fighting with even half his strength. Tobi has also stated that Itachi never ceased to amaze him. Despite his own impressive abilities, Itachi never underestimated his opponents, given his praise of Jiraiya, in which he noted to Kisame that if he fought him, they would either kill each other or hurt each other badly.

Not one for prolonged fights, Itachi's stamina was very low and could only use the Mangekyō Sharingan for three times a day before he needed a significant amount of rest. Even with that, and Itachi's health failing, along with the fact that he was holding back, Sasuke still could not defeat him during what would be their final confrontation. In his final moments of life, Itachi was able to perform a fūinjutsu, accomplishing all he had planned to do during that fight. Being a technical pacifist due to traumatic experiences from the Third Shinobi World War, Itachi did not actively take part in battle, only acting in self-defence, and mostly incapacitating his enemies instead of killing them if possible.

Taijutsu
Itachi possessed high-level taijutsu skills despite not specialising in it. This was demonstrated when he easily defeated Tekka, Yashiro, and Inabi — all of them his seniors and members of the Konoha Military Police Force. In Part I, he stopped Sasuke's Chidori with one hand and effortlessly disabled him during their reunion in the Land of Fire despite Sasuke's extensive taijutsu training for the Chūnin Exams. His skill in taijutsu allowed him to keep up with Naruto Uzumaki in his Nine-Tails Chakra Mode and Killer B respectively in individual fights.

Itachi was also noted to possess good reflexes and speed, particularly with his hand movements. This extended to collectively weaving both hand seals and throwing weapons, making it appear as if he could perform his techniques without seals; even skilled Sharingan users like Kakashi and Sasuke had difficulty seeing his movements. He was also proficient with the Body Flicker Technique and was able to attack a target, then immediately move to the location they had retreated to, giving them no time to initiate a counter-attack. In the anime, he also displayed a fair amount of physical strength, enough to cause small craters on the ground with a few kicks.

Ninjutsu
Itachi had great prowess with all of the three main types of techniques. Itachi's signature moves were techniques that involved the usage of crows, able to summon a large flock of them and use them both in his ninjutsu and genjutsu. This is seen primarily with his creations of clones which dissolve into crows, and crows that hide as shuriken. He could also create explosive clones.

Traditional to the Uchiha clan, Itachi could use Fire Release techniques, including the clan's giant fireballs the intensity of which was enough to bother even Samehada, and he could combine his proficient weapon skills with his fire attacks. He was also proficient with Water Release, able to perform them without an already existing water source. Itachi could catch his opponents off guard with drilling masses of pressurised water and large water dragons.

As a fully-trained Konoha ANBU, Itachi was also proficient in kenjutsu mostly demonstrated during his battle with Kabuto Yakushi after being reincarnated. As an ANBU, Itachi was also able to pass through the Sensing System Technique barrier without setting it off. Itachi also had high skill with fūinjutsu as seen when he performed Transcription Seal: Amaterasu on Sasuke, just moments before his death.

Shurikenjutsu
Even in his youth, Itachi could perfectly hit an intricate set of nine targets, one of which was hidden in a blind-spot, by accurately deflecting one kunai off another to ensure they struck their mark. During his fight with the controlled Nagato, he was able to blind Nagato's summons despite the shared field of vision granted by the Rinnegan. Itachi was also very skilled with shuriken, with Sasuke stating that Itachi was best with such tools, even more so than their own father. He could also infuse shuriken with fire for a devastating two-fold attack.

Sharingan
A true successor of the Sharingan, Itachi awakened and mastered the dōjutsu by the age of eight. He reached the stage where he could even have his Sharingan activated for extended periods of time, with minimal drain on his chakra levels.

Itachi was especially praised for his skills in genjutsu, known as one of the Uchiha's most powerful genjutsu users. His skill was such that he could cast one by merely pointing at someone or turning opponents' genjutsu against them. According to Ao, he could even use his genjutsu to take control of other individuals from a long distance. With the Sharingan, Itachi reached the point where he could use of one of the Uchiha clan's ultimate dōjutsu, Izanami, and also understood its counterpart, Izanagi.

Mangekyō Sharingan
Itachi possessed the Mangekyō Sharingan, which enabled him to use his most powerful techniques. With his left eye, he could use Tsukuyomi, a genjutsu that trapped opponents' minds in an illusory world, torturing them for what felt like days in a matter of seconds. With his right eye he could use Amaterasu, which created controllable black flames that could burn anything, including fire itself. His final technique was Susanoo, the, a technique that used both eyes to create a spectral being. It wielded the Sword of Totsuka, an ethereal sword with the ability to seal anything it pierced into the gourd that served as its hilt, and the Yata Mirror, a shield that could reflect any attack. With the Susanoo also came his most powerful long-ranged attack: the Yasaka Magatama. During his battle with Kabuto, he also demonstrated the ability to partially manifest and control the various stages of Susanoo with great mastery. The defensive power of his Susanoo is great enough to protect him from the full effects of a technique as powerful as Kirin despite it being destroyed and needing to be reformed from the technique.

Despite his mastery of the Mangekyō Sharingan, Itachi suffered greatly from its side effects. Each of the techniques bestowed by the Mangekyō Sharingan required vast amounts of chakra to perform, and left him fatigued afterwards, requiring him to deactivate his Sharingan altogether. From Part I, three uses of the Mangekyō seemed to bring him to this point. The other side effect was that his eyesight would gradually worsen since the awakening of the Mangekyō Sharingan, and the degradation would only quicken after every time he used it, which would lead him to eventually go blind, with his Sharingan forever sealed away. By the time Itachi activated his Mangekyō Sharingan during his final fight with Sasuke, Itachi's eyesight had deteriorated so much that Sasuke appeared to be a mere blur, his eyesight was so close to blindness that by the time he activated Susanoo, both Sharingan had lost the Mangekyō design, with only the red iris remaining.

Intelligence
Ever since he was a child, Itachi had a keen sense and awareness of what was happening around him. He was also blessed with the innate ability to perceive someone's nature. It was because of this that Itachi took great interest in the history of the village, and what their ancestors left behind. Due to his way of thinking, he was never bound by the limited view of "the clan" but actually thought of the village as a whole. It was also noted that at the age of seven, the young man reasoned on the level of a Hokage.

Itachi has been shown to be analytical and perceptive, being able to deduce the inner workings and weaknesses of powerful techniques, even while under pressure. He orchestrated his battle against Sasuke to bring about his desired outcomes, and even account for the possibility that his plan wouldn't go as intended by sealing his power into Sasuke and placing a special crow inside of Naruto Uzumaki. In the event that Tobi would come in contact with Sasuke, he transcribed Amaterasu to Sasuke's eyes in an attempt to kill Tobi when his guard was down. This lead the masked man to note that had he not kept a few secrets from Itachi, he would have died from his last trap.

On top of his perceptive skills, Kabuto also noted that Itachi possessed skill in deception due to Itachi's ability to read people's feelings, and this made him a ninja of lies up until his death.

Search for Tsunade Arc
After the Invasion of Konoha and the death of Hiruzen, Itachi and Kisame infiltrated the Konoha to find Naruto Uzumaki, the jinchūriki of the Nine-Tailed Demon Fox. However, Itachi has an ulterior motive in using his appearance to remind Danzō, Koharu, and Homura that he is still alive and not to think of harming Sasuke with Hiruzen dead. While Itachi stops for tea after Kisame suggested it, they attract the attention of Kakashi Hatake, who had Asuma Sarutobi and Kurenai Yūhi follow them. Making it out of Konoha with Asuma and Kurenai still in pursuit, seeing no more need to conceal their identities, Itachi and Kisame proceed to overpower them and Kakashi. After a short skirmish, learning that he is aware of them, Itachi activated his Mangekyō Sharingan and used Tsukuyomi on Kakashi before instructing Kisame to silence the Konoha ninja until Might Guy arrived and deflected Kisame's attack.

Learning that the ANBU have been informed of their presence, Itachi tells Kisame to fall back to avoid further confrontation as dealing with four jōnin-level shinobi would be problematic enough, before they track Naruto down to a hotel where he was staying with Jiraiya at the time. To ensure the Sannin does not meddle, Itachi uses a genjutsu on an attractive woman to draw Jiraiya away from Naruto. As he and Kisame confronted Naruto, Itachi is confronted by Sasuke before Jiraiya arrives with Itachi learning that the Toad Sage told Kakashi about Akatsuki. Allowed to fight his brother, Itachi uses his Mangekyō Sharingan to easily defeat Sasuke while him easily reaffirming Sasuke's need to get stronger. Jiraiya takes over the fight from there, using the Summoning: Toad Mouth Bind technique to trap the Akatsuki members before Itachi risked his health by using Amaterasu to allow himself and Kisame to escape.

Sasuke Retrieval Arc
At the end of Part I, Itachi made a cameo appearance as a silhouette during an Akatsuki gathering where they discussed Orochimaru's taking of Sasuke Uchiha as well as both capture of Kurama for the furthering of their plans.

Kazekage Rescue Arc
While Akatsuki was sealing the One-Tailed Shukaku, the members discovered that Team 7 and Chiyo were en-route to their location. Itachi volunteered to distract them, so Pain used the Shapeshifting Technique on Yūra to create a body-double for Itachi. The lookalike, under Itachi's control, engaged the Konoha ninja. Itachi was impressed by Naruto and Kakashi's improvements in strength. However, because the clone had only a portion of his ordinary strength, it was killed by Naruto's Big Ball Rasengan. Nevertheless, he was able to buy enough time.

Hidan and Kakuzu Arc
Itachi was present during the sealing of the Two-Tails.

Itachi Pursuit Arc
As Sasuke defeated Orochimaru, Itachi sensed something odd yet assured Kisame that it was nothing. Following Kisame's capture of Son Gokū's jinchūriki, Rōshi, Itachi and Kisame met with the rest of Akatsuki. There, they discovered that Sasuke, after being trained by Orochimaru for two and a half years, had killed his teacher. Sometime after Son Gokū was sealed, Zetsu informed them that Sasuke had been killed by Deidara's C0. However, though asked by Kisame if he was troubled by his brother's death, Itachi remarked that Sasuke is still alive.

Knowing that his end was near, Itachi sent one of his shadow clones to meet Naruto, who was looking for Sasuke. Although he only wanted to talk, Itachi is forced into defending himself as he asks why Naruto cares so much about a traitor like Sasuke. Upon hearing Naruto's intent to bring Sasuke back to Konoha, along with finding a way to stop Sasuke without killing him should he ever attack their village, Itachi smiled and is content with the youth's resolve. He then has one of his crows enter Naruto's body, telling the boy that he hopes he may never need to use it.

After his business with Naruto was done, another of Itachi's shadow clones went to meet with Sasuke. Sasuke exhibited an improvement in his abilities during their confrontation, so Itachi agreed to have their final battle at the Uchiha Hideout. He waited there for Sasuke's arrival, instructing Kisame to not let the other members of Sasuke's team interfere with the fight. Itachi and Sasuke met face-to-face and, while exchanging genjutsu, had a conversation about Madara Uchiha, and Itachi's "true" motives of wanting to take Sasuke's eyes. When Sasuke managed to escape Itachi's Tsukuyomi, the genjutsu battle ended and the ninjutsu battle began.

Itachi used Amaterasu, but Sasuke uses Orochimaru's power of shedding his skin to catch his brother off guard with a Fire Release: Great Dragon Fire Technique at Itachi's direction above although he only managed to burn one of Itachi's arms. Out of chakra, he told Itachi about his final technique that, like Amaterasu, was impossible to avoid. Sasuke then used his trump card, on Itachi.

However, with only his Akatsuki cloak burned off, Itachi managed to survive by using his Susanoo to defend himself. With Kirin having expended all of Sasuke's chakra, Orochimaru gained control and reappeared through his Eight Branches Technique. However, Itachi was easily able to cut off the seven snake heads, leaving only one behind whose mouth Orochimaru appeared out of. Orochimaru thanked Itachi for pushing Sasuke so far, thereby setting him free and allowing him to take control of Sasuke's body. Itachi, however, stabbed Orochimaru with the Totsuka sword to seal him away with Susanoo, removing the cursed seal from Sasuke's body.

As Itachi began to weaken, the Susanoo started to fade and Sasuke saw an opportunity to strike. This was in vain, as Susanoo was still able to protect Itachi with the Yata Mirror. His last option gone, Sasuke was pushed against a wall as Itachi stumbled closer to him, seemingly reaching for Sasuke's eyes. However, he instead poked Sasuke's forehead and smiled before saying, "I'm sorry, Sasuke… …It ends with this" before he finally succumbed to his illness and died.

Konoha History Arc
In the anime, three years ago before Sasuke's defection from Konoha, Nekobaa mentioned about Itachi, but was stopped by Sasuke from talking about him. After Sasuke defeated Nekomata, he told Sasuke that Itachi had defeated him in the past along with his ninja cats and asked Nekomata to fight Sasuke with all his might when he got older.

Later, Sadai, an assailant who entered the Land of Fire to capture Naho, mentioned to Sasuke about Itachi, the Uchiha Clan Massacre, and even about Sasuke being weak, which led Sasuke to defeat and punch him repeatedly.

Chikara Arc
In the anime, a reincarnated Itachi was summoned by Kabuto to battle Team Kakashi, who were investigating the massacre that he brought about in the Tonika Village to gain access to The Hole. Quickly after being summoned, Itachi's coffin vanished with Kabuto questioning if the Impure World Reincarnation was still incomplete.

Confining the Jinchūriki Arc
In an attempt to both impede Tobi and coerce him into joining forces during their initial encounter, Kabuto Yakushi demonstrated his capabilities by reincarnating many of the deceased members of Akatsuki, including Itachi, using Summoning: Impure World Reincarnation.

Shinobi World War Arc
When the Fourth Shinobi World War against the Allied Shinobi Forces commenced, Itachi was mobilised alongside Kakuzu and Nagato — who due to being crippled was being carried by Kakuzu. Later supporting the latter as they walked, the now isolated pair continued throughout the night, conversing about Akatsuki. Itachi remarked that their two dōjutsu together could achieve anything which was likely why their summoner would wait for the opportune moment to use their abilities. After pausing at a shrine and discussing Kabuto's influence on Tobi's plan, they marched onwards until they encountered Naruto Uzumaki and Killer B.

Surprised by Naruto's growth and the fact that he had subjugated the Nine-Tails, Itachi attempted to ask him something, but he instead attacked the pair involuntarily with his Fire Release: Great Fireball Technique. He discerned Kisame's death from B's possession of Samehada, and while exchanging both dialogue and blows with Naruto, was shocked and disappointed to learn of his brother's decision to destroy Konoha, and Tobi's awareness of the truth behind the Uchiha clan massacre. Imploring Naruto to keep the truth secret for the sake of his clan's honour, he then entrusted dealing with Sasuke to him. As Itachi confronted B, he caught him in a genjutsu after using his Fire Release: Phoenix Sage Flower Nail Crimson technique to attack him. However, fending off several attacks, he retreated atop Nagato's summon and activated his Mangekyō Sharingan. Much to Naruto's shock, the crow Itachi had placed inside him during their last encounter emerged.

As Itachi and the crow's eyes met, Itachi readied Amaterasu. However, instead of hitting Naruto, it had hit Nagato's other summon. Freed from Kabuto's control, Itachi turned to Nagato and engulfed him in black flames, before leaping towards Naruto. Itachi explained how he had implanted Shisui's eye into the crow, rigged it to use Kotoamatsukami with the command "protect Konoha" on whoever used his dōjutsu. This was originally meant for Sasuke in case he attacked Konoha with the Eternal Mangekyō Sharingan, overrode Kabuto's control over himself instead. Asked by B why he didn't just use Kotoamatsukami on Sasuke from the beginning, Itachi revealed that he had other intentions and that excluding augmentations, such as Hashirama Senju's DNA, Shisui's Mangekyō would take a decade to regenerate after using Kotoamatsukami. Itachi, along with Naruto and B, was then assaulted by a regenerated Nagato.

As Naruto and B fought Nagato directly, Itachi blinded both the King of Hell and the chameleon summon with a barrage of kunai. This allowed him to move undetected and free both jinchūriki from danger with his incomplete Susanoo. In response, Nagato used Chibaku Tensei in an attempt to lift and crush them with gravity. After careful analysis, Itachi surmised that attacking the sphere at the centre of the technique would effectively dispel it, so he proposed that they take advantage of Chibaku Tensei's attraction force to gravitate their strongest long-range techniques directly towards it. Using Yasaka Magatama in combination with the others' attacks, they confirmed his assumption and the sphere was broken. Before the dust settles, Itachi impaled Nagato with his Sword of Totsuka and asked Nagato to impart any final words before the sword sealed him.

After Nagato was sealed, Itachi stated that he would deal with the Summoning: Impure World Reincarnation technique as he had already formulated a plan, allaying Killer B's concerns by reiterating that every technique had a weakness. However, when Naruto decided to stop the war on his own, Itachi told him that despite becoming stronger, Naruto was forgetting all those who he wanted acknowledgement from and that with those egotistical thoughts, he would become like Tobi. Reminding him that his father became Hokage because of Kushina and those around him, he stated that if Naruto had the same dream, he should not forget his friends. Itachi then incinerated his crow, stating that the eye could not be reactivated for another decade and that Naruto, having inherited Shisui's will, could stop Sasuke without it. Realising that he tried to do everything on his own and still failed, Itachi refused to see Sasuke and resolved to leave Sasuke to his friends instead. After asking B to look after Naruto, Itachi departed.

On his way to stop Kabuto's technique, Itachi encountered Sasuke but pressed on. This caused Sasuke to chase him down and attempt to catch him with a hand of his Susanoo, but Itachi deflected this with one of his own. Bombarded by a flurry of questions from Sasuke, Itachi said he spared Sasuke at the massacre because of Sasuke's childhood innocence and his own desire to eventually be judged for his actions by a fellow Uchiha. Expressing his regret about the path Sasuke had chosen and partially blaming himself, he resolved to talk no further, which led Sasuke to retort that Itachi was still running away from him even in death. Itachi broke his silence to refute this, stating that he was not running away but going to stop the Summoning: Impure World Reincarnation technique. Itachi attempted to prevent Sasuke from following by using a flock of summoned crows to obscure Sasuke's vision. Upon arriving to Kabuto's location, he answered Kabuto's intrigue of how found him, stating that he could feel the source of Kabuto's chakra while under his control. However, Kabuto advised Itachi to not kill him if he sought to stop the technique. Detecting Sasuke behind him, Itachi noted that things were not proceeding as intended.

Kabuto tried to persuade Sasuke to his side, but failed and caused Sasuke to attack. Itachi deflected Sasuke's shurikens, informing his little brother that the Summoning: Impure World Reincarnation technique couldn't be stopped should Kabuto die. When Sasuke joined forces with Itachi, Itachi promised his brother that he would speak to him once Kabuto was defeated.

Kabuto obscured his vision to prevent being caught in genjutsu, and sent his snakes out to attack, but the brothers used their Susanoo to intercept and sever their heads. However, Kabuto eluded their attack and concealed his location by scattering his chakra. Then to Itachi's surprise, Kabuto revealed that he had found the Ryūchi Cave and attacked with his Sage Art: White Rage Technique.

As Itachi rushed to Sasuke's side, he was both deafened and blinded by Kabuto's technique, but still managed to protect Sasuke from Kabuto's advance. When Kabuto questioned whether Itachi could sense his chakra, Itachi replied stating that he possessed no such ability as he had made Kabuto think, but merely predicted Kabuto's intent instead. Kabuto then used Itachi's deceit to implant doubt and mistrust amongst the brothers, but Itachi retorted by asking if Sasuke remembered the time they dealt with a giant boar, with the two immediately taking action after Sasuke affirmed that he did. Itachi launched his Yasaka Magatama at the area surrounding Kabuto to prevent his escape, providing Sasuke with an opportunity to pin his snake tail to the ceiling. As Kabuto — now dangling from the cave's roof — seemingly attempted to use Sasuke's sword to sever his navel-snake, Itachi intercepted the swing but found himself impaled in the process. However, his body dispersed into a flock of crows, which allowed the real Itachi to commandeer the blade and sever one of Kabuto's horns.

Kabuto once again attempted to inveigle Sasuke's loyalty, but Itachi told his brother to not heed Kabuto's words, as Kabuto was an even more convincing liar than he was. He then explained that while their village does have its dark side and inconsistencies, he still remained loyal to it as. Despite his admitted fault for Sasuke's current state and as such, not being in any position to criticise him, he still desired to tell Sasuke something after Kabuto's defeat. In response to Kabuto's later claims of invincibility, Itachi declared that Kabuto wasn't aware of the true power of the Uchiha and that the ultimate eye technique which would decide his destiny was already prepared.

Anticipating Kabuto's next attack, Itachi used his Susanoo to protect Sasuke, but was himself incapacitated. As Kabuto moved to rewrite the talisman in Itachi's head, Sasuke encircled them both with a ring of Amaterasu, cancelling out Kabuto's technique through the flames intense heat. After his recovery, Itachi apologised to his brother, and then turned his attention to Kabuto and told him that though Kabuto was very different from himself, he could sympathise because in the past, he too couldn't appreciate his true self nor his limitations. He then went on to declare that comrades were there to do what you couldn't and that those who weren't able to acknowledge their own selves were bound to fail.

Itachi asserted that he had failed in the past and that the "Uchiha" name alone was nothing more than a display of his roots. Imploring Sasuke to not kill Kabuto but instead wait until his preparations were complete, the siblings came under attack once more, as a copy of Sakon — which emerged from the base of Kabuto's naval snake — transformed into Jirōbō and breached the protective circle of flames. Without pause, the brothers simultaneously used Amaterasu to incinerate the approaching, uncuttable web created by a copy of Kidōmaru. Trapped between more webbing and numerous invasive bones created by a Kimimaro copy, the two separated — with Itachi focusing on destroying the latter — and used their Susanoo to eliminate the threats. The siblings then retreated further into the cave, but this evasion was short-lived as Kabuto produced a copy of Tayuya to use an auditory genjutsu, which paralysed them both. As Kabuto produced a copy of Orochimaru's true form, Itachi chastised his belief that a person's reason to exist could be found through the imitation of someone they respected. Telling Sasuke to look into his eyes, he cast Tsukuyomi as Sasuke used his Sharingan genjutsu, effectively allowing them to enter each other’s minds and counteract Kabuto's technique in time to stop the copy of Orochimaru's true form from attacking them. After declaring that he would now use Izanami, Itachi was suddenly bisected by Kabuto who launched a surprise attack by emerging from the mouth of the subdued Orochimaru copy.

While Sasuke bought him enough time to regenerate, Itachi attacked Kabuto, who countered his attack by driving Sasuke's sword into Itachi's chest. Disappearing into a flock of crows, Itachi cut off Kabuto's horn once again. This sequence of event repeated itself several times until it was revealed that Kabuto was actually trapped inside Izanami, which would continue to loop this same sequence of events. Itachi explained to Sasuke that he wished to use this technique so Kabuto could acknowledge his real self before dying, unlike himself. After this, Itachi told Sasuke that he would stop the Impure World Reincarnation, that he had no more attachments to the living world, and that he was proud to be able to protect his village once more. He also added that ending the technique was the least he could do to alleviate some of the burden he had placed on Naruto. Raising the brille that had covered Kabuto's eyes, Itachi casted a genjutsu and ordered Kabuto to teach him the seals to stop the Impure World Reincarnation technique.

After being told the seals, Itachi has Kabuto perform them while his brother states he still could not forgive Konoha for what they had done to Itachi. Before the Impure World Reincarnation was cancelled, Itachi moved towards Sasuke with his hand outstretched to poke him as he always did in their youth, and stated that he could still make it. Before his consciousness faded completely, Itachi used his Sharingan and shared with Sasuke his memories and the truth of what had happened, leading up to the coup d'etat their clan had planned. Showing him this, Itachi told Sasuke that he no longer wanted to lie to Sasuke and contemplated whether things would have turned out differently had he told Sasuke the truth of what was happening at the time. Seemingly gesturing to poke Sasuke once more, Itachi told his little brother that he did not have to forgive him, but no matter what happened to him from that point onwards, he would always love him, resting his forehead on his little brother's as he imparted his final words to him and then disappeared, and his spirit went to the afterlife, leaving the corpse of an unknown Konoha shinobi behind.

Legacy
Knowing that his death was near, Itachi set up his final battle against Sasuke as redemption for what he did. Itachi removed Orochimaru and his influence from Sasuke and left behind an Amaterasu that would activate in the presence of Tobi's Sharingan. Though the latter act was designed to protect Sasuke from Tobi, it did not stop Tobi from revealing the true reason for the Uchiha Clan Massacre and the identities of the ones responsible: Konoha's higher-ups. Though Itachi hoped Sasuke would rebuild the Uchiha to be better than before, Sasuke was unable to let go of his grief nor ignore the suffering of his clan or his brother, and became a bitter enemy of Konoha as a result. But having expected Sasuke would take such a path after his death, Itachi entrusted a crow which had Shisui Uchiha's Sharingan implanted in its eye socket to Naruto.

Expecting Sasuke to eventually transplant his eyes to stave off the blindness that would come, Itachi planned for the crow to emerge from inside Naruto during their confrontation and compel his brother into protecting the village rather than destroy it. However, after Itachi was reincarnated by Kabuto Yakushi during the Fourth Shinobi World War and sent after Naruto, the crow's Kotoamatsukami broke him free from Kabuto's control instead. He aided the Allied Shinobi Forces by finding the summoner and forced Kabuto to release Impure World Reincarnation. Joined by Sasuke, Itachi succeeded in ending the technique, imparting final words that had Sasuke questioning whether or not he truly wanted revenge.

Inadvertently, Itachi also garnered praise from the five current Kage, who hailed the person who released the Impure World Reincarnation as a hero who protected the shinobi world. Even a reincarnated Hashirama Senju was greatly impressed by Itachi's actions and went as far as to note that Itachi was an even better shinobi than himself.

Naruto Shippūden 6: Road to Ninja
In the alternate world, Itachi appears as the leader of Akatsuki in the alternate universe Naruto and Sakura end up at. Working for Konoha, they help Naruto in the battle against Menma's pawns as Itachi rescues a captured Sakura.

Trivia

 * can be translated as "weasel".
 * Itachi ranked highly in the Shōnen Jump popularity polls for the series, continuously placing in the top ten and reaching sixth place once. In the latest popularity poll, he rose to fifth place.
 * He and Kisame were the first active Akatsuki members to appear.
 * Itachi and Kisame made a brief cameo appearance in the Hidden Leaf Village Grand Sports Festival!, where they were standing in line to use the bathroom, along with many other random characters.
 * According to the databook(s):
 * Itachi's hobby was visiting traditional Japanese cafés.
 * Itachi wished to fight Sasuke.
 * Itachi's favourite foods were cabbage and onigiri with seaweed in it, while his least favourite was steak.
 * Itachi had completed 340 official missions in total: 53 D-rank, 152 C-rank, 134 B-rank, 0 A-rank and 1 S-rank.
 * Itachi's favourite word was.
 * Itachi had always poked his younger brother, Sasuke Uchiha, in the forehead when they were younger, saying . This is referred to very poignantly with Itachi's last words, as he pokes his brother's forehead again and says,
 * Itachi is tied with Jiraiya for having the highest stat total in the databooks.
 * Itachi is one of the few people who knows the identities of both Naruto's father and mother.
 * Fittingly, the shinobi that was sacrificed for his reincarnation was a Konohagakure shinobi, indicating his affiliation with the village.
 * Amaterasu, the Shintō goddess of the sun, had a three-legged crow named Yatagarasu. In addition to having a technique named Amaterasu (which he used against Pain’s Giant Drill-Beaked Bird, which also had three legs), Itachi uses crows in his techniques.
 * According to Shintō mythology, Yatagarasu's appearance was regarded as an omen for either something really good or bad. His permanent appearance was through the Koto Amatsukami, namely Takagi no Kami and Amaterasu who sent Yatagarasu as a saviour to end Emperor Jimmu's war. This closely resembles Itachi's role, where he is freed through Koto-Amatsukami and becomes an important asset in the Alliance's efforts to end the shinobi war.

Quotes

 * (To Sasuke)
 * (To Sasuke) "Being the best isn't all it's made out to be. When you're strong, you become arrogant and withdrawn. Even if what you sought after was your dream."
 * (To Sasuke) "You and I are flesh and blood. I'm always going to be there for you, even if it's only as an obstacle for you to overcome. Even if you do hate me. That's what big brothers are for."
 * (To Yashiro, Tekka and Inabi) "You hold onto the organisation and your clan name. These things limit us and limit our capacities… These things deserve to be shunned. It is foolish to fear what we've yet to see and know!"
 * (To Yashiro, Tekka and Inabi) "I've had enough, there's no hope left for this pathetic clan. You forget what is most important to you because you cling to something small like your clan. True change cannot be made if it is bound by laws and limitations, predictions and imagination."
 * (To Sasuke)
 * (To Sasuke) "People live their lives bound by what they accept as correct and true. That's how they define "reality". But what does it mean to be "correct" or "true"? Merely vague concepts… their "reality" may all be a mirage. Can we consider them to simply be living in their own world, shaped by their beliefs?"
 * (To an infant Sasuke) "Don't cry, Sasuke. Your big brother is here to protect you, no matter what happens."
 * (To Kisame, after he related the story of the sharks) "We are humans, not fish. We don't know what kind of people we truly are until the moment before our deaths. As death comes to embrace you, you will realise what you are. That's what death is, don't you think?"
 * (Last words to Sasuke)
 * (About Shisui's teachings to him) "Self-sacrifice… A nameless shinobi who protects peace within its shadow… That is a true shinobi."
 * (About Konoha) "The village does have its dark side and its inconsistencies, but I'm still Konoha's Itachi Uchiha."
 * (To Kabuto) "Those who can't acknowledge their real selves are bound to fail."
 * (To Kabuto) "That (imitating someone you respect) is something you do in order to grow. You can't use it as a disguise to pretend to be someone you are not."
 * (Last words to Sasuke after reincarnation) "You never have to forgive me. No matter what happens to you from here on out, I will always love you."