Character Profile: Itachi Uchiha

Itachi is Sasuke's older brother, and a genius ninja who entered the battlefield at a young age. Itachi, at age seven, was already a ninja, and at eight had mastered the Sharingan, which is a special ability of the Uchiha clan. As a result, Itachi became cold and distant. By age 13, Itachi was made an ANBU squad leader, though it was so the Uchiha clan could have a spy among ANBU's ranks. However, Itachi spied on his own clan in turn for the Konoha leadership at the time while he was being mentored by Madara Uchiha. After seeing his friend Shisui die from falling off a cliff, Itachi obtains the Mangekyou Sharingan and expresses his true feelings for his clan after his clansmen attempted to force the truth out of him.

When the Third Hokage and Daizo learn that the Uchiha clan are planning a coup to take over the village, they assign Itachi the task of slaughtering his clan with his new power. However, in return, Itachi blackmailed them into letting Sasuke be sparred, and thus Itachi would take full blame. After he murdered his clan with Madara's aid, Itachi lies to Sasuke, saying that he was simply testing his strength, telling him:

Foolish little brother... you can't kill me, your hate's not strong enough... you're not strong enough. That's right, live in shame, run away, and live.

Taking his brother's words to heart, Sasuke was filled with the desire to avenge his family and become strong enough to kill Itachi, as Itachi had intentionally planned. Once leaving Konoha, Itachi joined Madara's Akatsuki organization, where he defeated Orochimaru when Orochimaru attempted to take his body, and became its top member.

When news of the Third Hokage's death came to him, Itachi returned to the Leaf Village on a mission with Kisame Hoshigaki to kidnap Naruto for the Nine-Tailed Fox demon sealed within Naruto. The pair encounter Kurenai, Asuma, and Kakashi, but while the three had no intention of letting Itachi and his companion leave quietly, they had little choice, as they are very easily defeated.

Though he failed, Itachi succeeded in stirring Sasuke back into his plans, attempting to expand his lifespan due to the Mangekyou Sharingan's side effects bringing him closer to death. Years later, Itachi confronts Sasuke in the final battle between the brothers, revealing that the Mangekyou Sharingan can be perfected once one brother kills the other and takes his eyes. Though claiming to be the victor after sealing Orochimaru, Itachi knells over with the last of his strength being to give Sasuke his Sharingan power.

Itachi's strongest attack is the Mangekyou Sharingan, which is the ability to enter another's mind and make them feel anything you want. For example, when fighting Kakashi, Itachi forces Kakashi to feel as if he is being stabbed with katanas for 72 hours in what was actually only a matter of seconds. This leaves Kakashi unconscious for several days. However, if you read manga chapter 392 it reveals an even more powerful move stronger than the Mangekyou and Amaterasu called Susano'o which was able to protect Itachi from Sasuke's lighting attack. The jutsu has two parts, a shield and sword. The shield is a rib cage of the god that surrounds the user protecting them from any harm and the sword is a very powerful move that was able to destroy Orochimaru when he appeared during the fight with just one swing.

Itachi's ninja level is unknown, though he was described by Asuma as an S-ranked criminal.

Itachi ages from 17 to 18 in part 1. In part 2 he is 21 years old.

I have done a lot of research and watched basically all of the anime series out there, thanks to Naruto Central and Naruto Fan, and I have a downloaded copy of all the manga issues. I have also done data research through various website and books including Wikipedia and Shonen Jump.

During this time, I found some new data "suggesting" that once a ninja goes rouge they are no longer classified as ranks such as a Chuunin, Jounin, Sanin, and the like, but are instead ranked by letter, graded by skill, criminal activities, and threat level. Then they are assigned a letter out of the following (please remember, this is just my theory):

F:

Basically, losers who can only do stuff academy ninjas can, or aren't ninjas and have very low skills as a warrior.

D:

Basically, a Genin or someone who has done a large amount of misdemeanors.

C:

Chunin or someone who has done a lot of misdemeanors AND a few bigger stuff such as a murder and stuff.

B:

Chunin or Jounin level, or someone who has done quite a bit or criminal activity such as murders and assassinations.

A:

This is held in reserve for people of at least Jounin level and does major crimes without discrimination.

S:

This is held in reserve to that of a major threat like someone capable of equaling a Kage and has done severe criminal activity like a lot of assassinations of major people and other TERRORIST-like activities.

U:

This basically translates to a super S-Class, and relates to anyone who is at a level were they can take on multiple S-Class ninjas with ease.

Now this type of ranking system is also used in real life by military intel bureau and international crime management organizations. In both the manga and anime, many people, including Jiraiya in episode 81 and 82, feel that all of the members in Akatsuki are in fact "s-class". So, in conclusion, lets just say he is a major bad ass.