Story-wise, it's hard to tell. After all, the player is basically intended to be the most powerful being in existence that is capable of doing it all. It is very possible that the main character is soloing the binding coil. Remember, technically there was no one helping the player against Titan nor Garuda. Ifrit, you can POSSIBLY infer that your party members were fellow captives.

I wouldn't be surprised, games like this do it all the time. Look at the Elder Scrolls series, it is completely canon that the main character ends up as the head of every major fiction of the game. Does it make sense? Not really, but clearly the main character is meant to be the second coming or something like that.