It's just a glimpse, but Rogue One: A Star Wars Story offers a little more Darth Vader in its new international trailer, and also expands upon the backstory of Jyn Erso (Felicity Jones).
New footage shows Jyn running from hostile aircraft as a young girl, and the Rebellion leadership explaining why they need her help. You also get to see a ragtag team assemble to steal the plans for the Death Star, as well as a the Death Star in action for a weapon's test - suggesting that previously seen footage of Jyn and her pals frantically flying in terrible conditions is actually them escaping a planet that has been attacked by the massive weapon.
There's even a hint that Jyn may be Force sensitive, (or at least, someone close to her believed in it when she was a child).
Rogue One: A Star Wars Story hits theaters Dec. 16.