Well Bahamut is one of Midgardsormr's children. The others are Azdaja, Nidhogg, Hraesvelgr, Tiamat, Ratatoskr and Vrtra. I just don't know in which order they were all born. I'm curious about that. I believe age equals power in the dragon world. I think Bahamut was the oldest, which exlains why he's the biggest. Hraesvelgr and Nidhogg resemble each other a lot, maybe twins. I don't know in which order the rest should be placed.