So Bahamut/Tiamat are Dawn/Dusk Wyrm, what about the rest of The First Brood?

[Naria]

Well, Bahamut and Tiamat being related to the Au Ra or another member of the First Brood in Othard would be one way to tie Othard back to Eorzea in a mythological sense and provide a convenient reason for why we wouldn't have heard about it before from travelers/scholars/refuges. It would as provide an excuse for Midgardsormr to still hang around or even tie in with Estinien's return. and maybe Tiamat will leave Azys Lla