The guess to Itachi's disease is most commonly MPA or Microscopic Polyangiitis. This seems to be a pretty common theory among people as most of his symptoms are textbook. MPA is a very rare auto immune disease that causes antibodies to attack blood cells causing them to bleed as they become damaged and inflamed.
However, Itachi Uchiha notably suffered from a terminal ailment, which raises a lot of questions. First and foremost, why would Itachi, of all people, be afflicted with a disease that plays such a major role in his death? Itachi's illness may serve a larger purpose regarding the plot, and his character.
As was later revealed, Itachi was already ridden with an incurable illness when he fought the final battle with Sasuke. Besides, his eyesight had already weakened due to excessive use of his Mangekyo Sharingan.
As mentioned, he was extremely powerful in his teenage years, even before reaching his peak. Had it not been for his illness shortening his lifespan, Itachi would have grown to surpass the greatest of shinobi and would have totally redefined levels of power.
1) Itachi Uchiha
Undoubtedly one of the most tragic characters in Naruto, Itachi Uchiha shouldered the burden of killing his own brethren to stop a coup d'état in the Uchiha clan, orchestrated by his own father. All this, in order to protect the village.
If Itachi never got sick he would have told Sasuke about why he killed the clan and there probably would have returned to the village and stop Danzo making Sasuke never going to the kage summit.
Sasuke Uchiha
In his case, he surpassed Itachi during the 4th Great Ninja War, where he gained the power of the Rinnegan, along with the Six Paths Yin chakra.
Despite his impressive achievements, there is no way Itachi can beat Obito in his most potent form. Obito Uchiha, in his strongest form, was the Ten Tail Jinchuriki. This means he had massive chakra reserves and endurance.
Itachi Uchiha was a special member of the clan, known to be among the strongest and smartest characters not just among the clan but the entire shinobi world.
Itachi would have surpassed Madara Uchiha if things were different for him. He learned every powerful Jutsu at a very young age and had a whole life to hone his skills and strength. However, he died too soon and his true potential never saw the light of day.
What is Neji's IQ? Neji is supposed to be a genius and characters like Asuma and Jiraya score a 4.5. While characters like Itachi, Hiruzen, Minato, Shikamaru, etc score a 5.
So this time I want to impart this truth with you, you don't even have to forgive me, and no matter what you do from here on out, I will love you always.” These were Itachi's last words when he stood in front of Sasuke just before he was about to break from the reanimation.
Nothing happened to Itachi's left arm. He just chose to wear his sleeve like that as a fashion statement to look cool. That style really isn't uncommon when it comes to Japanese Manga, Anime, and Video Games. For Example, Auron wore his sleeve like that in “FINAL FANTASY X” which was released all the way back in 2001.
I cried so much when he told Sasuke he loved him and released the edo tensei. “I will love you always.” That episode has always and will always make me cry. Hell, writing about this episode makes me tear up.
Because he was finally at peace. Although he definitely let Sauske win, he was terminally ill and wanted Sauske to be the one to kill him, as it was Sauske's goal and only way to get strong. Itachi smiled because he was with his little brother whom he loved in his final moments.
Itachi wasn't strong, he was super smart. Obito feared his smartness. He knew Itachi would destroy any plan of obito as long as he's alive. Obito was not afraid of dying, he was just afraid of his plan getting ruined.
kakashi will put up a very good fight but would lose to itachi like 7 times out of 10 he would win 3 times because of his performance against asura and deva path of pain who were the strongest paths of pain.
Itachi was able to fight against Naruto Uzumaki in his Nine-Tails Chakra Mode, something that Pain could never do. He was also able to incapacitate Nagato Uzumaki, and it is quite easy to see that he could definitely have taken on and defeated Pain in combat.
One of Pain's underlings, Itachi Uchiha was, surprisingly, stronger than he was. Itachi was a user of the Mangekyo Sharingan and had two of the most hax Jutsu at his disposal in Amaterasu and Tsukuyomi. His Susanoo was considered to be unbeatable due to him wielding two ethereal weapons.
Who's The Smartest? Kakashi is stated to be smarter than part 2 Shikamaru. Itachi should by all reasoning be as smart as Kakashi.
Itachi was not scared of Jiraiya, he just understood the level of difficulty he faced in that matchup. In Naruto battles were not always about who's-stronger-than-who, but rather who has the better matchup due to their skillset.
If Minato were alive, he would've made sure that Naruto never lacked anything in life, including comfort and a loving parent. Minato would have been Naruto's rock who'd help him become a splendid human being.
During his time with the organization, Itachi completed several important missions, recruited other members, and partnered with Kisame and Juzo. Itachi died at the age of 21 during his battle with Sasuke.
Itachi Uchiha Quotes about Pain
“Time doesn't heal anything, it just teaches us how to live with pain.”