The Rogue One trailer has finally dropped, with tons of hints about the new film as well as the wider Star Wars story. Bring on the speculation!
With the conspicuous absence of Darth Vader, the main antagonist of Rogue One seems to be the enigmatic man in white, shown leering over Imperial plans and, later on in the trailer, walking calmly into the devastation of a vicious battle.
But who is this imposing villain? There are more than a few clues about this already, and he could very well connect Rogue One to the now non-canon Expanded Universe.
Grand Admirals: The Highest Imperial Rank
From his white robes and military insignia, we can tell that this character (played by Ben Mendelsohn) is a very high ranking Imperial officer, possibly second only to the Emperor himself. His rank insignia is that of an an admiral, but it's the white robes that have everyone talking.
Imperial uniforms are almost always grey and black, with two notable exceptions: Imperial Security Bureau officers (ISB), and Grand Admiral Thrawn from the Expanded Universe. Thrawn is the main antagonist for one of the EU's most popular and widely read trilogies, Timothy Zahn's The Thrawn Trilogy, a direct continuation of Return Of The Jedi. These books were hugely influential, shaping the canon of the Expanded Universe.
The Lucasfilm Story Group are very much aware of what came before, which is why The Force Awakens parallels the EU in many ways (especially in the character of Kylo Ren, who mirrors Jacen Solo). So could Mendelsohn's character draw inspiration from Thrawn?
Thrawn wasn't just an admiral in the EU, but a Grand Admiral, which is important as only the Grand Admirals were permitted to wear the white uniform. Zahn created the rank when he wrote The Thrawn Trilogy, and it was reintroduced to the main canon by Chuck Wendig with his novel Aftermath. Interestingly, there's already a character in Aftermath which parallels Thrawn, known only as the Operator.
Thrawn himself is a fascinating character, dedicated to re-establishing the Empire's hold on the galaxy after the Battle of Endor. Considering the popularity of this character, and his impact on the EU, it's entirely possible that Mendelsohn's character is meant to parallel Thrawn in Rogue One.
That would mean this new character is incredibly ambitious, vicious, and has his own plans for the Empire's expansion. All of this would fit very well with the story of Rogue One, giving the characters an antagonist to rival the Emperor in the original trilogy. Of course, there's a simpler explanation for who Mendelsohn's character could be.
The Director Of The ISB
The ISB are a terrifying faction of the Imperial military: a Stasi-esque not-so-secret police force, the ISB specialise in surveillance, apprehending traitors, and keeping survivors of the Jedi Order good and oppressed. Oh, and they also wear white uniforms... or at least, they did in A New Hope and the EU.
Thanks to the cartoon Star Wars: Rebels, the ISB are alive and well in the current Star Wars canon, with Agent Kallus as one of the main antagonists in the show. Kallus may not wear a white uniform, but it's possible the white robes are reserved for the highest ranking agents/officers of the ISB.
The ISB are a perfect fit for Rogue One antagonists. The trailer set Jyn Erso up as a renegade, one who has a list of charges against her from the Empire. And who's responsible for arresting criminals under Imperial order? Yep, it's the Imperial Security Bureau. If Mendelsohn is the director of the ISB, that would make him a formidable opponent, as he pursues our heroine across the galaxy. He might even have a vendetta against her, as Jyn has clearly evaded Imperial capture several times.
So there's the two possibilities for Mendelsohn's character, and he could even fulfill both options: a Grand Admiral who is the ranking officer for the ISB. This would make him something entirely new in the Star Wars universe, with Thrawn's ambition and ruthlessness combined with the daunting power and control of the ISB.
Either way, we've definitely got an epic new villain on our hands, the latest to "hold Darth Vader's leash." Which is awesome.