At least one major rumor about the upcoming season of "Star Wars Rebels" was confirmed today at "Star Wars" Celebration Europe with the release of the new trailer.
Grand Admiral Thrawn, a fan-favorite villain from the Expanded Universe (now called "Star Wars" Legends) will indeed play a role in Season 3 of the Disney XD series, where he'll be voiced by Lars Mikkelsen, brother of "Rogue One: A Star Wars Story" actor Mads Mikkelsen.
“You couldn’t’ have grown up a 'Star Wars' fan without encountering Thrawn in 'Heir to the Empire,'” Executive Producer Dave Filoni said. “It was a dark time when there weren’t any more movies, and it blew our minds that there could be more.”
Introduced in 1991’s “Heir to the Empire,” the first novel in the “Thrawn Trilogy," the Imperial officer rose to prominence following the deaths of Darth Vader and the Emperor as he pieced together what remained of the Empire. In "Star Wars Rebels" he'll be tasked with tracking down and crushing the Ghost crew and the budding Rebellion.