Tiamat and Bahamut.

What do you think is the connection there? There are several random possibilities and outrageous theories (like, maybe, Future Esthar style theories) that connect the two. Bahamut kinda had his own story if you can improvise one, but what about Tiamat? They seemed... related, somewhat, but are they? Just think about them both.

Tiamat is just a guardian of Ultimecia, just another monster in your way, right? Well, he has a lot of similarities to Bahamut. Time to pull out a crazy theory out of my ass:

Perhaps Tiamat and Bahamut one and the same. Ulti's in a completely different time period, so say she somehow acquired Bahamut from Squall or the party in the future. Of course, it's not a valid arguement since getting Bahamut is optional, but still, something to think about.