Hmm... it actually does... (look to the right of Ramuh, you can even see Atomos' right most horn in the fog). If it's not Atomos, there's at least
something behind Odin?? I can see Atomos playing a much bigger part than what we've initially thought, and that it could connect with Odin, Bahamut, Louisoix and the other primals.
I think the 6 elemental primals being paired with its traditional opposites has more to do with simple design/composition, rather than giving a hint about the story. But IMO Odin and Bahamut being prominently featured
does give a hint.
One other thing that just struck me that I haven't really seen mentioned: The huge beam of white light from Odin's sword. It may be that light beam that stopped Bahamut and that's why Louisoix fades to white... When you look at the white beam from Odin's sword/Louisoix fading to white, Odin's prominent placement in the poster, Odin's appearance in the ARR trailers (and assumed appearance in the opening to ARR), and the (possible) horse sound at the end of End of an Era, I think they all point to pretty good evidence that Odin is a big part as to why Bahamut didn't destroy everything. *Please note though that I'm not saying Louisoix
turns into Odin because there's no evidence for that and frankly the idea seems a lil silly to me.*
btw here's the original pic for reference (taken from another thread)