Well Xenoblade Chronicles 2's official site is up. Nothing terribly new:
http://xenobladechronicles2.nintendo.com/
But I wanted to post it because it's a nifty thing to have and track as it updates.
But I also wanted to point out that Rex has a very brief bio and I totally called some key points:
"An energetic young man who works as a salvager to make ends meet. He meets Pyra and comes to play an enormous part in determining the future of the world."
I said months ago he was probably a scavanger and inventor. His armor is made of scrap machine parts and he has a grappling hook that looks constructed out of the same spare parts.