Bahamut from XVI needs to have his own league and not just for the Zettaflare but also for how good Dion is as a character, how gorgeous the design of Bahamut is, the music, the fight, etc.
I feel like Bahamut is just there to make everyone feel his power in some games since we know he is practically the strongest, i said "practically" since we have seen him in different forms and i still don't know which one is canonically the strongest, ive seen 14 and 16 bahamut and they do not mess around