Quote Originally Posted by Colorful View Post
Except he didn't, he became the primal Phoenix from all the prayers around Eorzea, didn't he? He's using borrowed power.
The fact alone that he was able to do that is all the information you need. The only other person we know of to become a primal was Lady Iceheart, and she wasn't even a fraction of the same strength. Furthermore, he was holding Bahamut back before he even became Phoenix, and cast a powerful binding spell.