Itachi Uchiha

was a prodigy of Konohagakure's Uchiha clan. After murdering his entire clan, sparing only his younger brother Sasuke, he joined the international criminal organisation known as Akatsuki, whose activity brought him into frequent conflict with Konoha and its ninja (including Sasuke) who sought to avenge their family. Following his death, Itachi's motives were revealed to be more complicated than they seemed and that his actions were only ever in the interest of his brother and village, remaining a loyal shinobi of Konohagakure to the very end.

Background
Itachi was the first son born to Mikoto and Fugaku Uchiha. His early childhood was marked with violence: when he was four years old the Third Shinobi World War broke out and he witnessed firsthand many of the war's casualties; shortly after the war ended the Nine-Tails' attack on Konoha occurred and Itachi – his parents nowhere to be found – was left solely responsible for keeping his infant brother, Sasuke, safe. The death and destruction he experienced at such a young age traumatised Itachi and made him a pacifist. He began to study history, not just of his clan or his village but of the world, and by doing so he gained a broader appreciation of what was important. Learning so much enabled him to understand how events of the past came to happen and, when he applied that same understanding into the future, he became concerned for where things were going.

Though peace-loving, Itachi was a natural prodigy in the shinobi arts, praised as the best of his generation. At age 7, Itachi graduated from the Academy at the top of his class; at age 8 he mastered the Sharingan; at age 10 he passed the Chūnin Exams; at age 11 he entered the Anbu; by age 13 he was promoted to Anbu captain. Itachi's accomplishments were a source of great pride for his family, his father viewing him as proof of the Uchiha's future prosperity and his brother viewing him as a model to live up to. Itachi spent a great deal of time with Sasuke, training with him (though rarely actually training him) and giving him the recognition their father did not. But for all the attention he received, few truly understood Itachi, believing his isolation to be a result of the gap between his abilities and theirs and not his dissatisfaction with the shinobi's life of conflict.

The Nine-Tails' attack had soured relations between Konoha's leadership and the Uchiha, the former believing the latter to be responsible. The Uchiha were relocated to a corner of the village, isolating them from the rest of the village and making it easier to monitor them. The Uchiha felt wronged by this treatment and began planning a coup d'état. Fugaku, head of the Uchiha and the coup's chief conspirator, encouraged Itachi's advancement into the Anbu's ranks as a means of spying on the village. Itachi, however, knew an Uchiha coup would lead to intervention from other villages and ultimately start another World War, something he could not support. He instead became a double agent, reporting the Uchiha's actions to the Third Hokage and his advisers in the hopes it would help them find a peaceful resolution.

Itachi shared the burden of betraying his clan with Shisui, his best friend, brother-figure, and a like-minded Uchiha. But as time went on it became increasingly clear that peace could not be achieved. Shisui attempted to use his Kotoamatsukami on the Uchiha's leaders to compel them to negotiate, but his right eye was stolen by Danzō Shimura before he had a chance. His own options exhausted, Shisui entrusted his remaining eye to Itachi and begged him to protect the village and their family name before drowning himself in the Naka River. Itachi was anguished by Shisui's death, enough to awaken his Mangekyō Sharingan. When the following day some Uchiha, already suspicious of Itachi, accused him of murdering Shisui and staging a suicide, Itachi lost his composure and attacked them, defeating them easily. A rift was created between Itachi and his family, and his warnings to them to reconsider what they were doing fell on deaf ears. Itachi then braced himself for combat but Sasuke pleaded for Itachi to stop. Not wanting Sasuke to witness such a scene or wanting him to know the truth, Itachi bowed and "apologised" for his actions.

Although the Third Hokage still wished to negotiate with the Uchiha, Danzō Shimura recognised that there was no longer an outcome that could see the Uchiha clan's survival. He explained this to Itachi and left him a choice: support the Uchiha's coup and have the whole clan, including Sasuke, killed in the ensuing conflict, or accept the assignment to wipe out the clan before the coup started and be allowed to spare Sasuke. Itachi chose his brother. While making final preparations, Itachi discovered a masked man sneaking around Konoha. From observing him he came to believe the man was truly Madara Uchiha bent on provoking some new conflict. Itachi approached him with an offer: he would assist "Madara" with wiping out the Uchiha, taking vengeance against them for abandoning him decades earlier, if Madara would spare the village. The man, otherwise known as Tobi, agreed.

In one night Itachi and Tobi slaughtered the entire clan. Itachi took it upon himself to personally execute his parents. Despite his betrayal, they bore him no ill-will, instead telling him in the moments before they were killed that they were proud of him and requesting that he take care of Sasuke. Racked by grief for his actions, Itachi saw in Sasuke the only person suitable to punish him for his crimes. In order to set Sasuke on this road he cast himself as the villain, done by allowing Sasuke to find him standing over their parents' bodies and using Tsukuyomi to torment him with visions of their murders. Sasuke fled, fearing his own death, but Itachi chased him down to divulge the lie he had concocted: he killed their family to test his mettle and now wanted to test himself against the only remaining challenge to him, the little brother he'd never loved. He encouraged Sasuke to become strong enough to kill him and take revenge, and to that end suggested he acquire a Mangekyō Sharingan of his own. Itachi left, but was surprised to find Sasuke already pursuing him with a newly-awakened Sharingan. Sasuke's attempt at vengeance failed and he passed out, but not before seeing Itachi cry with remorse.

For his final business in the village, Itachi visited the Third Hokage and reported his mission completed, much to the Third's surprise and disappointment. Itachi requested that the Third look after Sasuke, which the Third vowed to do. Concerned that not all of Konoha's leadership would follow this request, Itachi also met with Danzō and threatened to tell every secret he knew about Konoha to its rival villages if any harm came to Sasuke, which Danzō assented to. Itachi left the village publicly a traitor but secretly with a new mission: to infiltrate Tobi's organisation, Akatsuki, and keep it from moving against Konoha. He was partnered with Kisame Hoshigaki, with whom he bonded over their shared notoriety for killing their own countrymen. At some point after joining Akatsuki, Orochimaru tried to steal Itachi's body in order to gain the Sharingan, but Itachi easily deflected him and severed his left hand, forcing him to leave the organisation. To find a replacement for Orochimaru, Itachi helped recruit Deidara, whose art he defeated with his Sharingan's genjutsu; Deidara would forever after swear vengeance for the humiliating defeat.

Itachi at some point contracted an incurable terminal illness. He kept himself alive through the years with medicine and sheer willpower so that he could live long enough to die by Sasuke's hand.

Personality
From a young age, Itachi was quiet and insightful. He lived at a distance, observing individuals and ideas without getting directly involved so that he could fully understand them. Although this approach prevented him from becoming close with many people, it enabled him to think and act without prejudice or preconceptions, instead evaluating things strictly on their own merits. He would think about shinobi and origins of the village and its future. For this reason he never had the self-righteous loyalty to his clan that was so common among the Uchiha; though he loved his family and wanted the best for them, he knew there were more important things than the Uchiha's aspirations.

Despite being a pacifist by nature, Itachi felt his own needs were secondary to the greater good's; to that end he became a shinobi. He trained tirelessly to improve himself as quickly as he could and subjected himself to all of the shinobi life's inconveniences without complaint for the simple motivation of being useful to others. Being so accomplished as a ninja enabled Itachi to approach problems less violently than others would, satisfying his peace-loving nature. These two extremes of his personality came into conflict as events moved toward the Uchiha Clan Downfall; he did not want to harm his family and sought a peaceful resolution, but knew that the path with the least bloodshed would be the clan's extermination. As the inevitability of the massacre became more apparent, Itachi's normally polite attitude to his clansmen became more violent, criticising them openly and lashing out at them for the choices that sealed their fates and his own.

Despite the traumas he endured from killing his own family, Itachi did not blame those among Konoha's leadership who gave him the mission; though he did not trust Danzō Shimura on a personal level, he knew Danzō only had the village's best interests at heart. But Itachi – partly out of the necessity of his assignment to join Akatsuki – was greatly changed after the massacre, rarely if ever showing emotion. He became more prone to displays of force and permitted certain violent habits of his partner, Kisame Hoshigaki, under the pretence that it furthered Akatsuki's goals. Itachi could not and would not fully shake his pacifist ways, and would run from confrontation or rein in Kisame if the likelihood of collateral damage became too high for themselves or others. While Kisame would sometimes protest, he considered Itachi a good friend and would listen to his instructions.

Konoha's protection was always forefront in Itachi's mind, but it was his dedication to his brother, Sasuke, that took priority in every situation. From the time of Sasuke's infancy, Itachi tasked himself with looking after him. They'd spend whole days together in the woods around Konoha having adventures and accomplishing self-appointed missions. When Itachi began to become an accomplished ninja and took much of their father's attention, Itachi would make special time to fill their father's shoes for Sasuke's benefit, at times even refusing his father's wishes in order to make Sasuke happy. Sasuke, wishing to be just like his older brother, would often ask Itachi to train him in the ninja arts. Itachi would almost never do so, poking his forehead and promising to train him some other time.

It was Sasuke's safety that ultimately convinced Itachi to go through with killing the rest of the Uchiha, believing his own damnation was worth it if it ensured Sasuke's survival. Even though he did it for Sasuke, Itachi wanted to be punished for his crimes and selected Sasuke as the one to take vengeance against him. To push Sasuke in this direction, Itachi withheld the true reason for his actions and instead took on the persona of a man who had no love for his younger brother. Per the persona, Itachi cared about Sasuke only because of the eyes that he could take to gain Eternal Mangekyō Sharingan. His actions in Akatsuki were meant to reinforce this persona, and whenever he met Sasuke over the years he would taunt his weakness and encourage him to get strong enough to kill him. His plan was that, once he had been killed, Sasuke would be hailed as a hero. Itachi never wanted Sasuke to learn the truth surrounding the Uchiha's massacre, and if he did he hoped the memory of a hateful older brother would cause him to not believe it.

After he died and was reincarnated, Itachi discovers that his plans largely failed; Sasuke is not a hero and he did find out the truth about what Itachi did. Naruto Uzumaki points out to Itachi the flaw in his plans: he had been trying to manipulate Sasuke rather than be honest with him and trust in his own strength. Acknowledging the mistake, Itachi is free to be himself instead of the persona he fabricated, being openly kind to others and displaying a dry sense of humour even in stressful situations. He is finally open with Sasuke when they meet again, admitting what he did and even sharing information Sasuke did not already know. He apologises to Sasuke for failing in his responsibilities as an older brother, wondering if being up front with Sasuke from the beginning might have allowed them to avoid the Uchiha's destruction. In their final moments together, Itachi tells Sasuke he does not need forgiveness and that he will always love him no matter what.

In the anime, Itachi had a very strong bond with Shisui, so much so he had an off feeling during his mission when Shisui was in danger and rushed back to investigate.

Appearance
Itachi had onyx eyes under which were long, pronounced tear-troughs. He had jet-black hair that was pulled back in a low ponytail and his face was framed with centre-parted bangs that extended to his chin; the ponytail and bangs grow longer over the years. His overall appearance is very similar to Sasuke's. When he lived in Konoha, his casual clothes consisted of a black shirt with the Uchiha clan symbol on the back, bandages around his ankles, and black sandals. He wore tan 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 the standard Akatsuki cloak and a slashed Konoha forehead protector to symbolise his broken ties with the village. The cloak's high collar would obscure his ponytail. He would sometimes unbutton his cloak to mid-chest and rest his left arm there, rather than in the sleeve. Under his cloak he wore clothes similar to the rest of Akatsuki: mesh armour with navy accents under an identical T-shirt with a simple white belt around the waist and dark blue pants. On his right ring finger was his Akatsuki ring, which was red and bore the kanji for. He wore purple nail polish on his fingers and toes and a necklace that had three silver rings with red gems inside them.

Abilities
Itachi was a ninja of prodigious talent, evidenced by the rapidity with which he rose through the ninja ranks. He was equally proficient in all three main types of ninja skill and gained praise from allies and foes alike. Even Orochimaru, one of the Sannin, openly admitted Itachi was stronger than he was. His younger brother Sasuke, who significantly improved his abilities over the time-skip, wasn't able to truly defeat Itachi in their final battle and it was the latter's terminal illness that killed him in the end. Being a pacifist at heart, Itachi did not actually like fighting and would avoid it when he could. When he couldn't, he would end the fight as quickly as possible, all the while holding himself back. Even when restrained in this way, Kakashi Hatake, Kurenai Yūhi, and Asuma Sarutobi (all of whom were experienced jōnin) were still pushed to their limits against Itachi.

Chakra and Physical Prowess
As an Uchiha, Itachi's chakra was naturally strong, but his actual chakra reserves were very low, preventing him from participating in prolonged battles. In Part I, he could only use the Mangekyō Sharingan three times in a day before he needed significant rest. Constant usage of his Mangekyō during his final battle with Sasuke contributed to his death as it worsened his illness.

Although Itachi was very skilled with taijutsu – enough to easily defeat three members of the Konoha Military Police Force – he rarely actually got involved in hand-to-hand combat. What he did consistently display, however, was impressive speed and reflexes, particularly with his hand movements. This extended to both throwing weapons and hand seals, making it appear as if he could perform his techniques without seals; even skilled Sharingan users had difficulty keeping track of him. His speed allowed him to attack first in a battle, then immediately move to the location his opponent retreated to, giving them no chance to initiate a counter-attack. In the anime, he was even able to keep up with the famous Shisui of the Body Flicker.

Ninjutsu
Itachi could summon crows, which he would typically call forth in flocks to swarm opponents and distract them. He even integrated crows into clones of himself that would draw opponents' attacks. He was likewise able to create shadow clones that could lure in opponents before exploding. In addition to crows and clones, Itachi was practised with fūinjutsu, particularly those that would activate upon seeing specific people's Sharingan.

Bukijutsu
As a fully-trained Konoha Anbu, Itachi was skilled with a sword, which was his primary weapon during the Uchiha Clan Downfall. His comfort area as an Uchiha, though, was shurikenjutsu. Even in his early childhood, Itachi could perfectly hit an intricate set of eight targets, one of which was hidden in a blind-spot, by accurately deflecting two kunai off two other kunai in such a way that every kunai hit a target. His throwing speed was unprecedented, enough to keep up with and therefore negate the advantages of the Summoning: Lightning Flash Blade Creation. He was as equally comfortable with kunai, and at times used kunai like swords against opponents that wielded actual swords.

Nature Transformation
As an Uchiha, Itachi had a natural affinity for Fire Release, mastering the clan's Great Fireball Technique at a very young age. He would often coat shuriken with fire to increase their offensive capacities. He was also a skilled Water Release user, able to perform the Water Dragon Bullet Technique without an already existing water source and with just a one-handed hand seal. His other chakra natures included Wind Release, Yin Release, and Yang Release.

Genjutsu
Consistent with his pacifist nature, Itachi specialised in genjutsu typically performed with his Sharingan. His illusions, which often involved crows, could be initiated after only the briefest moment of eye contact, and even targets that knew to expect genjutsu might not immediately realise that they'd fallen prey to him. Even avoiding eye contact with him didn't guarantee safety, as he could cast genjutsu by merely pointing at someone. In addition to basic illusions, Itachi could use genjutsu to share information or psychologically disable opponents, allowing him to end fights before they even began. According to Ao, he was the only person who could use his genjutsu to take control of other individuals outside the range of even the Sensor Division. If he ever came up against other genjutsu users, he could turn their genjutsu against them.

Sharingan
Itachi awakened and mastered the Sharingan by the age of eight, demonstrating skill and power superior to most members of his clan. He keeps his Sharingan active near-constantly with minimal drain on his chakra levels. The Sharingan allowed him to see chakra and predict movements, as well as facilitate his use of genjutsu. With the Sharingan he could perform Izanami, a counterpart to the more dangerous Izanagi.

Mangekyō Sharingan
Itachi awakened the Mangekyō Sharingan after the suicide of Shisui Uchiha. Its design was three spiralling curves around the pupil. With his left eye, he could use Tsukuyomi, a genjutsu that trapped opponents' minds in an illusory world, torturing them for what seemed like days in a matter of seconds. With his right eye he could use Amaterasu, which ignited whatever he looked at with black flames that would burn anything, including fire itself. He had the ability to extinguish Amaterasu, but never displayed the sort of shape transformation that Sasuke later would.

Having unlocked the abilities of both his Mangekyō, Itachi could use Susanoo. With its simplest manifestations he could produce extra arms or bones to improve his options in a fight. When used in full, Itachi was surrounded by a spectral warrior that would protect him from all damage, even jutsu as powerful as Kirin. In addition to the chakra swords and Yasaka Magatama common to all Susanoo, Itachi's Susanoo wielded the Sword of Totsuka – an ethereal sword with the ability to seal any person it pierced into its gourd—hilt – and the Yata Mirror – a shield that was said to reflect any attack by changing its chakra nature to counterbalance an attack. The simultaneous use of both weapons made Itachi's Susanoo essentially invincible.

Itachi was not immune to the Mangekyō Sharingan's side-effects: each of the Mangekyō's techniques required vast amounts of chakra to perform and left him so fatigued afterwards that he had to deactivate his Sharingan altogether. Every time he used his Mangekyō Sharingan his eyesight deteriorated, a process that would progressively worsen on each occasion. Early uses of the Mangekyō would only cause his eyes to bleed, but by the end of his life he reached the point where he was nearly blind, most things looking to him like mere blurs. He does not suffer these shortcomings after his reincarnation and can use all his Mangekyō techniques without problems.

Intelligence
Just as he was emotionally distant in his personal life, Itachi would typically be physically distant in combat, avoiding direct conflict so that he could observe an opponents' actions and abilities. He thought quickly and remained calm in a fight, enabling him to respond with maximum efficiency and with little likelihood of misjudging circumstances. If an opponent exceeded his expectations or posed a legitimate challenge to him, Itachi would freely admit it. His studies of history gave him remarkable foresight and a cost-benefit understanding on par with the Hokage; he took several precautions for Sasuke and against Tobi that he planned would activate after his death, and if not for Tobi's interference, these precautions would have worked exactly as intended.

Search for Tsunade
After the Konoha Crush and the death of the Third Hokage, Itachi and Kisame use Itachi's prior experience as an Anbu to infiltrate the village undetected. They are nevertheless noticed by Kakashi Hatake, who sends Asuma Sarutobi and Kurenai Yūhi after them to determine their identities and purpose. Itachi and Kisame lead them to an isolated location and reveal themselves. Asuma and Kurenai engage them but pose little challenge and it is only due to the timely arrival of Kakashi that they are saved. Itachi uses Tsukuyomi on Kakashi, but is surprised that Kakashi not only remains standing afterwards but that he knows they and Akatsuki are seeking the Nine-Tails. Itachi instructs Kisame to capture Kakashi to find out what else he knows and kill the others, but Kisame is parried by Might Guy. With things escalating, Itachi and Kisame decide to withdraw.

Itachi and Kisame track the Nine-Tails' jinchūriki, Naruto Uzumaki, to Shukuba Town. Because Naruto is under the protection of Jiraiya, Itachi uses a genjutsu on an attractive woman to draw Jiraiya away. They confront Naruto and contemplate how to apprehend him. Before they can make a decision they are interrupted by Sasuke, who heard about Itachi's return and attacks him with Chidori. Itachi easily deflects it and then breaks Sasuke's wrist, but Jiraiya returns before things can go further. Not wishing to get drawn into a fight with Jiraiya, Itachi taunts Sasuke's weakness, incapacitates him with Tsukuyomi, and then makes to escape. Jiraiya attempts to stop them with Summoning: Toad Mouth Bind, but Itachi uses Amaterasu so he and Kisame can break through.

Despite his seeming intentions to capture Naruto, Itachi's only real reasons for returning to Konoha were to, in the wake of the Third's death, remind Danzō Shimura and the rest of the Konoha Council that he was still out there and that they should not do anything to harm Sasuke.

Sasuke Recovery Mission
Itachi and the rest of Akatsuki assemble to discuss the progress of their plans as well as Sasuke's recent alliance with Orochimaru.

Kazekage Rescue Mission
While Akatsuki is sealing the One-Tail, they learn that Konoha ninja are converging on their location. Just as Kisame volunteers to delay Team Guy, Itachi volunteers to delay Team 7. Nagato uses his Shapeshifting Technique to make a body-double of Itachi that he controls remotely, which he uses to intercept Team 7. Team 7 coordinates against him and Itachi is impressed by Naruto's growth, but he still manages to catch him in a genjutsu. He torments Naruto for his failures to protect his friends, specifically Sasuke, until the genjutsu is broken by Naruto's team-mates. Itachi, his body-double not having his full power, is eventually defeated by Naruto's Big Ball Rasengan. He nevertheless succeeds in buying enough time to complete the One-Tail's sealing.

Itachi Pursuit Mission
After Kisame captures the Four-Tails, Akatsuki convenes to seal it. Before the sealing gets underway they are informed that Sasuke has killed Orochimaru after two-and-a-half years of training with him and is now coming after Itachi. Deidara and Tobi go after Sasuke following the Four-Tails' sealing, and Akatsuki later receives reports that all three have been killed. Kisame consoles Itachi afterwards for now being the last Uchiha, but he replies that Sasuke is still alive. Even had he died, he says there is still another Uchiha, alluding to Tobi's survival as well.

Tale of Jiraiya the Gallant
Knowing that his end is near, Itachi sends a shadow clone to find and meet with Naruto. When Naruto attacks him, Itachi insists he only wants to talk. He asks Naruto what Sasuke means to him and what he will do if ever Sasuke moves against Konoha. Naruto replies that he is Sasuke's brother – a better brother than Itachi is – and that if Sasuke ever attacks the village he will defend it without killing Sasuke. Itachi is happy with this answer and gives Naruto some assistance for this purpose: a special crow that he stores within Naruto's body. (He does not tell Naruto the crow's purpose, but the crow, implanted with Shisui's Mangekyō Sharingan, will react to seeing Itachi's eyes and compel whoever has the eyes to protect Konoha. Since he expects Sasuke will take his eyes at some point, the plan is for the crow to reestablish Sasuke's loyalties to the village after Itachi is dead.) Having business elsewhere, the shadow clone disperses.

Another shadow clone allows Sasuke to track him to one of Akatsuki's lairs. Sasuke attacks him, displaying the new abilities he's learned, and in doing so convinces Itachi that he has gotten strong enough. The shadow clone arranges to meet with Sasuke at the Uchiha Hideout before it disappears. While Itachi waits for Sasuke, he has Kisame patrol the hideout's perimeter and permit nobody but Sasuke to enter.

Fated Battle Between Brothers
When Sasuke arrives they start by trading genjutsu. At Sasuke's request Itachi tells him about Tobi, who also goes by Madara, as well as the mysteries of the Mangekyō Sharingan and the even more powerful Eternal Mangekyō Sharingan. Itachi expresses his disappointment that Sasuke has not gained his own Mangekyō, but says he can use Sasuke's eyes to gain an Eternal Mangekyō all the same. The genjutsu exchange ends when Sasuke breaks free of Itachi's Tsukuyomi, thus beginning the real fight. The volleys of ninjutsu quickly spill outside, where Sasuke and Itachi compare their Great Fireballs. When Sasuke's starts to pull ahead, Itachi uses Amaterasu. While trying to hit Sasuke he ends up igniting the surrounding forest, but does finally manage to catch Sasuke. Sasuke sheds his skin to escape the flames and performs multiple Fire Release: Great Dragon Fire Techniques while Itachi is off-guard. Itachi avoids them, but Sasuke informs him that Itachi wasn't his target.

After Sasuke's attack, storm clouds gather and lightning brews, allowing Sasuke to attack Itachi with Kirin. Although the hideout is destroyed, Itachi survives thanks to his Susanoo. With his Susanoo active, Itachi approaches Sasuke. Having used all his chakra to perform Kirin, Sasuke activates his Cursed Seal of Heaven and out of desperation to defeat Itachi unleashes Orochimaru. Orochimaru springs from Sasuke's body using the Eight Branches Technique and states his intentions to take finally take Sasuke's body for his own. Itachi, having prolonged the battle in order to draw Orochimaru out, pierces him with Susanoo's Sword of Totsuka, sealing Orochimaru away and removing Sasuke's cursed seal.

Itachi resumes his approach, telling Sasuke his resolution to now take his eyes, and Sasuke makes futile attempts to keep him away. Susanoo continues to protect Itachi, but it degrades as he labors near and Itachi starts coughing up blood. When he finally reaches Sasuke, Itachi appears to grab for his eyes but instead only pokes his forehead. (The poke seals Amaterasu in Sasuke's eyes, set to activate against Tobi's Sharingan in order to protect Sasuke from him.) Itachi apologises to Sasuke and says this is the end before succumbing to his disease and falling dead.

Power
In the anime, Kabuto Yakushi reincarnates Itachi to be used against Team 7. The summon fails almost immediately afterwards, causing Kabuto to wonder if the Impure World Reincarnation was still incomplete.

Fourth Shinobi World War: Countdown
When the Fourth Shinobi World War looms, Kabuto approaches Tobi – who survived the implanted Amaterasu – offering to join forces. To that end he reincarnates Itachi and four other dead members of Akastuki as offerings for Tobi's war plans.

Fourth Shinobi World War: Confrontation
When the Fourth Shinobi World War begins, Itachi is mobilised with the rest of Kabuto's collection of reincarnated ninja. Itachi is paired with Nagato, who he carries because of Nagato's damaged legs. They discuss Akastuki and how little they, particularly Nagato, actually knew about the organisation; both were only pawns kept by Tobi because of their dōjutsu, and now they've been revived so Kabuto can use them for the same reason.

Itachi and Nagato are found by Naruto and Killer B. Itachi learns several things as Kabuto forces him to fight them: Naruto's Nine-Tails Chakra Mode indicates he's finally gained control of the Nine-Tails; B's use of Samehada is proof Kisame is dead; Naruto tells him that Sasuke now works to destroy Konoha, having been told the truth of the Uchiha Clan Downfall by Tobi. Itachi and Nagato continue attacking but give advice to Naruto and B about how to evade them. When he has an opening, Itachi calls out the crow he planted in Naruto before his death and allows it to use its genjutsu on him, overriding Kabuto's control with its pre-programmed mission to protect Konoha.

Now free to do as he wishes, Itachi joins Naruto and B against Nagato, using Amaterasu on him and his summons. Itachi continues to eliminate Nagato's summons and also saves B and Naruto from being killed by Nagato himself. Nagato uses Chibaku Tensei to try and restrain them, but the three join forces to destroy it. Itachi stabs Nagato with the Sword of Totsuka before the dust settles, sealing him away and ending the battle. Itachi then decides to personally take care of Kabuto in order to end the Impure World Reincarnation. Before leaving, he destroys the crow and Shisui's eye with Amaterasu so it doesn't fall into the wrong hands and entrusts Sasuke's reform to Naruto.

Fourth Shinobi World War: Climax
Nagato had been able to locate Kabuto's location while they were together, and Itachi now moves on a direct course there. He inadvertently crosses paths with Sasuke along the way. Feeling he is unworthy of Sasuke, Itachi tries to avoid him and his questions. When Sasuke persists, Itachi admits that he made a mistake manipulating Sasuke along a path that he wanted, which has put Sasuke in a worse position than he ever intended. As they near Kabuto's lair Itachi tries one last time to shake him, only to be disappointed when Sasuke joins him shortly after he confronts Kabuto. Sasuke moves to kill Kabuto, but is blocked by Itachi, who explains that Kabuto must be kept alive if the Impure World Reincarnation is to be broken. Sasuke offers to help on the condition that Itachi will finally talk to him afterwards. Itachi agrees.

Kabuto obscures his vision to prevent being caught in a genjutsu and attacks. Itachi and Sasuke block with their Susanoo, only to find that they have lost track of Kabuto. Itachi realises that Kabuto has achieved Sage Mode and quickly defends Sasuke before he can come to harm in Kabuto's sneak attack. Itachi reminds Sasuke of a mission they went on as children to hunt a boar, which they reenact with their Susanoo against Kabuto. Kabuto avoids them and commandeers Sasuke's sword, which he uses to attack Itachi. Itachi takes the sword back from him and uses it to cut off the tip of one of Kabuto's horns.

Kabuto tries to turn Sasuke against Itachi, pointing out all the lies and distrust Itachi has been showing Sasuke for years. Itachi admits his faults, but promises to tell Sasuke something after he's performed his Izanami. Kabuto is confident that he cannot be defeated since they can't kill him and because of the precautions he's taken to avoid genjutsu. He manipulates the cave to confine them and uses Strange Transmission Distant Shadow to perform a variety of other ninja's long-range jutsu, trying to create an opportunity to access Itachi's head and regain control of him. Sasuke becomes increasingly earnest to kill Kabuto, but Itachi pleads for him to wait until Izanami is ready.

While Itachi and Sasuke deal with Kabuto's recreation of Orochimaru, Kabuto bisects Itachi. Itachi's reincarnated body regenerates and he uses Sasuke's sword to cut off more of the same horn as before. This creates a sensory loop independent of vision that traps Kabuto in eternal battle; that is Izanami. Kabuto has the chance of escaping Izanami by accepting the fate he now tries to fight by taking on others' powers, Itachi's gift to him because of their perceived similarities. He raises the brille that cover Kabuto's eyes and uses a genjutsu to make Kabuto perform the hand seals that will end the Impure World Reincarnation.

While Kabuto performs the hand seals, Sasuke tells Itachi that he won't forgive Konoha for coercing Itachi the way that he was and that he will continue to conspire against the villages despite Itachi's wishes. Itachi listens without response. When he is engulfed in light and the Impure World Reincarnation begins to break, he faces Sasuke and admits to everything Sasuke has been told about him, even imparting some of his own memories to Sasuke to fully dispel the lies he's told. He reaches for Sasuke, seemingly meaning to poke his forehead again, but instead gives Sasuke a head bump, symbolising he no longer saw Sasuke as a child, but an equal. He tells Sasuke that he wants no forgiveness and promises that he will love Sasuke no matter what he decides to do. His reincarnated body dissolves and his soul returns to the afterlife.

Legacy
By his own design, Itachi had a profound influence on Sasuke's life. His instructions on the night of the Uchiha Clan Downfall for Sasuke to gain power at any cost caused Sasuke to isolate himself from other people and avoid companionship. When he realised that he was getting attached to the members of Team 7 and, from his perspective, failing to get stronger because of them, he joined with Orochimaru, propelling him along the path towards Itachi's death. But once Itachi is dead, his plans start to fail due to the interference of Tobi, who continues the trend of power and vengeance started by Itachi to Sasuke's detriment. Itachi is able to make amends with Sasuke once he's reincarnated, wiping Sasuke's prejudices clean and allowing him to start deciding things for himself.

Upon learning the entire truth about Itachi, Sasuke reverts to the great admiration he had for him when they were children and follows in his brother's footsteps. He does not want to see Konoha, the village Itachi sacrificed so much for, destroyed and therefore works against Tobi and Madara to end the Fourth Shinobi World War. He also sees the reason in Itachi's decision to make difficult choices and be hated for them, and for that reason gives himself the task after the war is concluded to become the world's darkness, using his power to force peace and unapologetically kill any that threaten it. Though this is again a great divergence from Itachi's plans, another of Itachi's plans redeems him: Naruto, at Itachi's insistence, eventually convinces Sasuke of the errors he has made without killing him after their final battle.

Itachi's influence would extend beyond Sasuke: Danzō Shimura, despite his difference of opinions with Itachi, believed him an unsung hero of Konoha who worked selflessly for the village's good; the five Kage, despite not knowing about Itachi's involvement, hailed him as the world's saviour for ending the Impure World Reincarnation; Kabuto Yakushi remembered who he truly was as a result of Itachi's Izanami and, inspired by him, resuscitated Sasuke when he was on the verge of death.

Posthumously, he would become an uncle as his brother would have a daughter with his wife named Sarada.

Road to Ninja: Naruto the Movie
In the alternate world, Itachi is the leader of Akatsuki. They are hired by Konoha to assist Naruto in the battle against Menma. Itachi rescues a captured Sakura during the fight.

Creation and Conception
In Naruto Hiden: Jin no Sho Character Official Data Book, Kishimoto revealed that Itachi was originally conceived before the series began, as the leader of Konoha's Special Assassination and Tactical Squad, dubbed the, which would have been a 70-man group divided into four teams, specialising in assassination and other illicit operations. In Kishimoto's original rough sketch, Itachi wore a bandana-style forehead protector, a skin-tight t-shirt, gloves, a coat tied around his waist, and had several scars including an x-shaped scar on his chin. Elements of this concept were later incorporated into Danzō Shimura and the Anbu.

Trivia

 * can be translated as "weasel".
 * Itachi consistently ranks highly in the Shōnen Jump popularity polls for the series, his highest to-date position being fifth most popular character.
 * 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.
 * Studio Pierrot's Settei sheets of Itachi show that he was 130 cm as a genin, 148 cm when he joined the Anbu and 170 cm around the time of the Uchiha Clan Downfall.
 * 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.
 * According to the fourth databook, Itachi was very fond of sweets. dango were his favourite.

Quotes

 * (To an infant Sasuke) "Don't cry, Sasuke. Your big brother is here to protect you, no matter what happens."
 * (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 Sasuke)
 * (To Naruto) "However strong you become, never seek to bear everything alone. If you do, failure is certain."
 * (To Naruto) "You don't become the Hokage to be acknowledged by everyone. The one who is acknowledged by everyone becomes the Hokage."
 * (About Konoha) "The village does have its dark side and its inconsistencies, but I'm still Konoha's Itachi Uchiha."
 * (Last words to Sasuke after reincarnation) "I failed. I won't put myself above you and tell you this and that, it's too late. So this time for once, let me tell you one small truth. It's all right if you never forgive me, but no matter what you become, I will always love you."