From the preview:
Every great story needs a great protagonist. And every classic struggle needs a villain worth your time.
We've said before that the Rise of the Empire expansion for Star Wars™: Rebellion adds a whole new chapter to your Galactic Civil War, and it does. The expansion brings new rules for cinematic combats that you'll be able to play out with several new units. You'll be able to undertake dozens of new missions, construct brand new technological terrors, pursue new Rebel objectives, and surprise your opponents with a wealth of new advanced tactic and action cards.
And you'll have eight new leaders to drive all this action—four each for the Empire and Rebel Alliance.