"Dark Naruto!!" (闇ナルト!!, Yami Naruto!!) is chapter 493 of the original Naruto manga.
Naruto tries to defeat his "inner darkness", the product of his lonely childhood and the lone obstacle in his efforts to tame the Nine-Tails. They are equally matched, so the fight does not go anywhere. Since this is an internal struggle, Naruto returns his attention to the real world and asks Motoi how Killer B overcame the evil in his heart but Motoi couldn't. Naruto then requests that Motoi ask B, however, Motoi weighed down by the guilt of having once tried to kill B stated once again that he could not. He then offers to tell Naruto about B's background so that maybe Naruto could find the answer himself.