So, there's one final optional summon to go: The legendary god-dragon Bahamut. Remember way back when in the game? Come on, use your noggin. We went up against him back on the Dragon's Peak, but were forced to flee him and his cute baby-Bahamuts. I think it is about time to give them a surprise visit.
Let's just hope the babies didn't grow up too.
So where is Bahamut's Lair? From Lake Dohr, fly east and then south to the southeastern bit of the world map. From the east, go towards Bahamut's Lair and enter.