Dark Naruto

is the manifestation of Naruto Uzumaki's inner hatred born from the Land of Lightning Island's Falls of Truth.

Apperance
From what is shown Dark Naruto appears to look just like Naruto except with completely black eyes.

Fourth Shinobi World War arc
After Killer Bee refuses to train Naruto, Motoi guides Naruto and Yamato to the Falls of Truth, the place where Bee trained to control the Eight-Tailed Giant Ox. He instructs Naruto to sit in a platform and close his eyes. Soon after Dark Naruto appears, berating Konoha's people for how quickly they changed their ideals of Naruto and have started sucking up to him which sickens him. He mentions that he is the manifestation of the darkness that exists in the heart of Naruto and that Nine-Tailed Demon Fox has taken a particular liking to him. Dark Naruto exclaims that he is the real Naruto and that Naruto is an impostor. As a result, both start to fight but Naruto realizes they have the same techniques, skills, and tactics. As a result, their fight is drawn out and Naruto mentions that it will take a long time to settle it. Later Naruto awakens and tells what happened to Yamato and Motoi. Motoi says he must defeat the Dark Naruto in order to learn how to control the Nine-Tails. He appears once again after Naruto returns to the Falls of Truth. He is angered by him because he makes an image of his autograph, but he talks back to Naruto, saying how he suffered because of the villagers. However, Naruto says he must have faith in himself, what starts to weaken the Dark Naruto and makes him attack Naruto, asking what's the reason of his existence then. So Naruto says he is really him and thanks him for everything, hugging him when he tries to attack Naruto and saying it was all gonna be alright. Letting go of his own anger at their past, Dark Naruto's eyes lighten and he gives into Naruto's warmth, disappearing into Naruto.

Later, when Naruto goes inside of himself to learn how to control the Fox, it expresses surprise at how it can no longer sense the 'real' Naruto.