An interview with Dave Filoni at NewYorkDailyNews.com has some fans wondering who it could be. Here's a brief snippet:
Executive producer Dave Filoni has confirmed that Grand Admiral Thrawn — who split duties with Maul as the big threat of Season 3 — will be the arch villain for the show's final season, which will run for 15 episodes.
"He's still the one that is watching for them and that they're running from and their main competitor," he tells the Daily News. "Which is different, we've never done that over two seasons before."
However, Filoni also hints that there may be a bigger villain lurking in the shadows.
"There may some other villains more arch than him, hiding somewhere … we'll have to wait and see," he says, with a little of that signature teasing he's known for.
Fans are already aware of another classic enemy that will be joining Thrawn's forces for the fourth season — Noghri warrior Rukh. Many will recall the character's pivotal role in the Legends continuity's Thrawn Trilogy and Filoni has tried to stay true to that portrayal.
"I try to keep those things as close as possible," he says.