Deep inside Naruto's mind the Demon Fox watched from its cage as images consumed one exterior wall of the sewer it was sealed inside. Nine hundred and eighty-seven screens showing exactly what each clone observed. Chuckling at the savage fighting style, it settled in to watch the show.
Contrary to popular opinion the demon fox had nothing to do with the ferocity displayed by its prison. The boy was a natural berserker when he was well and truly angered or pushed too far.
Oh, it had truly tried to shape its jailer in the boy's youth. Tried to instill a need for stealth, deception, trickery, and manipulation. To some extent it had been a great success. In pranking the boy was unmatched, unfortunately, it did not seem to transfer to his methods of combat. A great deal of effort had been expended to teach the boy skills and brighten up his dismal lifestyle.
Then he had to succeed in becoming a ninja.
After that point the rage for all Leaf shinobi overwhelmed the fox. Only when its life was in jeopardy, or the boy forced the matter, could the demon even consider aiding the boy. All those who served as ninja of the leaf village were its enemies and must be destroyed. Such were the terms agreed upon and a demon always keeps to the letter of a bargain struck.
Now that the boy was no longer a leaf ninja. It could be much more effective in helping the brat survive.