Star Wars: The Old Republic update 3.0 is on the horizon, and it appears Revan will have a large part to play per this new teaser trailer.
For those who didn't play Knights of The Old Republic on Xbox, Revan was the main protagonist and suffered from amnesia. His story is followed up in a novel released after the game, and reveals his fate after the events in KOTOR. Basically, Revan played an important role as both a Jedi and Sith, no less, during the Mandalorian and Jedi Civil Wars.
This isn't his first appearance in SWTOR though, as he appeared in a previous Flashpoint, but it is unknown exactly what part he will play in update 3.0 as Bioware is content with teasing players for the moment.
At least we think it's Revan, but we aren't alone in our assumption, as many players who have finished the Rakata Prime Flashpoint pretty much figured this out from the get-go.