[Ulquiorra]

Suiton. We are building toward Naruto vs. Sasuke. Naruto has Sasuke beat in one element. But Sasuke has him beat in another. Naruto has to have a counter for Sasuke's katon. Water seems like a no brainer.

Originally Posted by Last_Hope

But the elemental affinity isn´t something they can control.

You can only have one elemental affinity, but you can master all five elements. Elemental affinity just means you have an easier time learning that element.