The main story of this expansion is exactly the same for the Empire and the Republic. Altough, in a point of this story, there are short class missions for each of the eigth classes.
Curiously, the main story of this expansion has is prologue released in the previous expansion (Rise of the Hutt Cartel), in a storyline composed of four instances (called Flashpoints in this game), named "Forged Alliances". The player cannot do the story of Shadow of Revan without completing this prologue first.
Fourth expansion of the game (in technical terms), and second major expansion that raise the level cap of the game, from 55 to 60.