Board Thread:Fourth Databook/@comment-24577388-20141105025614/@comment-945885-20141105104012

They don't "all of a sudden" have multiple natures.

We already know that it's common for jonin to be proficient in at least three nature transformations. And that's all they are: proficiencies.

Nature transformation is not some sort of holy grail. We don't need to see every single ability in a character's repetoire to know that they have a repetoire of various abilities. These are things that they've trained in, in order to use them when the need arises.

This isn't like Avatar where characters are born with the ability to use only certain elemental techniques. They're born with an affinity for one element and then learn how to perform others.

As many of these characters have been training in ninjutsu for decades, it isn't strange that they would be proficient in multiple transformations. Especially when it comes to jonin ranked characters, since we already know they tend to have multiple.