Board Thread:Theories and Speculation/@comment-27082825-20150116155842/@comment-27082825-20150121160110

BeyondRed wrote: Don't think Yamato said anything to that effect in the manga, but Jiraiya did. He said it was unheard of for Nagato to master all six five natures, but he may have been referring to the fact that Nagato did so by age 10. That said, I certainly get the impression that Kishimoto didn't originally intend to have so many characters (including Jiraiya himself) be capable of using four or even all five natures.

Well are they confirmed users? Or is it possible that those excess elements are just potential and not actual capabilities?