Quote Originally Posted by Kraco
Well, they didn't wait very long to find out. Sakura began to heal him immediately. I mean, if your skin gets damaged like that, it's not a matter of a few days in any case. Maybe Naruto would have healed in a couple of days if left unattended. But since they intend to follow Oro, they don't have time to waste.

I also wonder if it was a wise decision not to tell Naruto anything. If he knows nothing, the next meeting with Oro will end up identically to this one. If he knew, though, that he became a mindless beast who attacked even Sakura, he might fight back and only use three tails. But now he thinks Oro knocked him unconscious, so he will be all the more angry and pissed off at the next meeting. Who knows, maybe enough to sprout the fifth tail. And then a real hell will break loose.
Very true but I don't think we will be seeing a fifth tail. After three Naruto completely loses control and travels within the seal. At that point the Kyuubi takes control and floods Naruto's body with its chakra trying to approximate its original form, as much as possible. Thats the important part, if Naruto could use more of the Kyuubi's power at that point then he would, so I would say that for now Naruto can't go beyond four.

I also think that there is some other reason why Naruto is suddenly able to use that much of the Kyuubi's power, anger alone can't be the trigger. If you think about it, the angriest we've seen Naruto's was when he was trying to stop Sasuke from leaving the village. If all he needed to be able to use so much of the Kyuubi's power was anger then we would have seen more than one tail at that point, so I think there is something else that dictates the number of tails that are formed.

I also find it very interesting that Naruto went four tails against Jiraiya, again if his anger is the trigger what could Jiraiya have ever done to make Naruto that angry, when they were just training. To go four tails Naruto has to become completely irrational, even against Oro and Kabuto they had to taunt and provoke him just for him to go that far and he already hated them so much.

So there is another reason why Naruto can only go four tails now and I suppose whatever that reason is, it is also why he wasn't able to go beyond one before.