The power system of the Naruto world relies primarily on three main arts: Ninjutsu, Taijutsu, and Genjutsu. While ninjutsu involves the manipulation of the five basic natural elements, taijutsu is the art of hand-to-hand combat. Genjutsu, which is quite easily the most underrated of the three, focuses on illusionary techniques.

Genjutsu was initially introduced to us in Naruto chapter 6 on November 8, 1999, in Shueisha's Weekly Shonen Jump Issue #48. Since then, genjutsu have played a significant role in the story, even becoming the ultimate threat for the entire world of ninja at the end. Throughout the run of the Naruto series, there have been multiple powerful genjutsu users, but among the humans, none managed to reach the same enigmatic status as Itachi Uchiha, who was eventually surpassed by his brother by adulthood in Boruto.

Itachi Uchiha was a legendary user of genjutsu , and his control over these tremendously powerful arts was shown to us quite early in the story when he faced Kakashi Hatake in Chapter 142. When the two clashed, Itachi used Tsukuyomi, which allows him to create an illusionary world where he controls space and time. In the real world, Itachi had cast his genjutsu only for a mere second, but in the world of Tsukuyomi, Kakashi stated that an eternity had passed and that he had been tortured for quite a long time, breaking him completely mentally. Had Might Guy not saved Kakashi, things would have been even rougher for him. In fact, without the help of Tsunade, Kakashi would have been bedridden for a significant portion of his life, showcasing Itachi's immense capabilities when it comes to using genjutsu.

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