So in each version, they naturally make mention of their respective legendaries... but there isn't one time that they mention the other versions legendary. By this I mean, I have version Y, and of course a good portion of the story revolves around Yveltal and the power it holds and blah blah, but there isn't one time that they mention anything about Xerneas.
Now, I don't know how it was in the 3rd generation as I never played them, but in all the previous ones, they made some sort of mention of the opposite or related legendaries at some point of the story.
I just thought this was weird and maybe worth discussing. They did make it seem that they were so old that almost no one knew anything about these Pokemon, so maybe that's got to do with it. I might be completely mistaken of course, but I don't remember reading anything about Xerneas in my version (and I imagine vice versa in X.)
Now, I don't know how it was in the 3rd generation as I never played them, but in all the previous ones, they made some sort of mention of the opposite or related legendaries at some point of the story.
I just thought this was weird and maybe worth discussing. They did make it seem that they were so old that almost no one knew anything about these Pokemon, so maybe that's got to do with it. I might be completely mistaken of course, but I don't remember reading anything about Xerneas in my version (and I imagine vice versa in X.)