Birth by Sleep Just a thought of mine. Spoilers

we all should have known that Sora was the chosen one from the beginning for those of you who thought Riku and mickey were on equal grounds but they aren't. Remember what Kairi wrote people. I can't remember all the words but here I go.
We pray for our sorrows to end- obviously a new hope
and hope our hearts will blend- Ven's heart going into Sora's
there are many worlds- obvious
same sky, same destiny- Sora and perhaps he is the key wielder who will bring chaos and ruin also as he is of the peace
one sky, one destiny- one chosen one, one key wielder(prophecy)

 

but have you noticed that it corresponds with what has happened so far?

 

this is just a guess but it could be her grandmother i think. she may have told her stories about the keyblade masters

 

And seeing as she sorta met one of them, maybe she remembered them?

I'm still wondering if she'll fully remember herself from Radiant Gardens as a child.​

 

I think its just a way of saying whats happened kingdom hearts at the end of kingdom hearts 2.

Oh and the full letter is in my signature.