Dark Naruto

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

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.

Quotes

 * (To Naruto) "Why didn't you sign those autographs at Ichiraku? They all...suddenly changed their tune and tried to suck up to you. What a couple of annoying assholes..."
 * (To Naruto) "If I've made one mistake, it's letting myself recklessly catch the eye of that Nine-Tails guy."