Quote Originally Posted by Lemuria View Post
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.
When he held Bahamut back, he was trying to summon the Twelve as primals. When he killed him, he was using a country's worth of prayer and an ungodly amount of aether vacuumed up by Tupsimati. Phoenix is probably one of the strongest primals ever summoned.