'Star Wars Rebels: Spark Of Rebellion' Trailer, Spoilers: Executive Producer Dave Filoni Says Thrawn Is The Most Challenging Character [VIDEO]

"Star Wars" has been a popular franchise for almost 4 decades now, and is only growing ever more popular with each of their slated franchise offerings. Star Wars has been well-known for the quality and fun of their movies, but they seem to also be leaving their mark on television, as well.

In October 2014, the Disney Channel debuted the new "Star Wars" animated series, "Star Wars Rebels: Spark of Rebellion," and the positive reception just snowballed, resulting in a very successful first season, a critically-acclaimed second season, and prompting the animated show to be renewed for a highly-anticipated third season.

Just recently, a new trailer for "Star Wars Rebels" Season 3 was unveiled in "Star Wars Celebration" that was held in London. The trailer features Grand Admiral Thrawn who was present in the 1991 novel, "Heir to the Empire" by Timothy Zahn. Grand Admiral Thrawn is a humanoid with glowing red eyes, and he is blue-skinned. It was revealed that his voice will be provided by Lars Mikkelsen, who is the brother Danish actor, Mads Mikkelsen, another Star Wars cast who will appear in Rogue One, Blastr reported.

In the panel, Dave Filoni, executive producer of "Star Wars Rebels," revealed that Thrawn was the most challenging character they have ever casted. He knows that fans wanted it. In addition, through video with the panel, Zahn announced that he is working on a new novel which features Thrawn, and it will be simply titled, "Thrawn." The release date would be April 2017.

The Twitter account of Star Wars also tweeted a reveal by Filoni about a plan to expand the Star Wars Rebels universe.

"Star Wars Celebration" also featured new footage and unveiled the new poster for their upcoming film, "Rogue One: A Star Wars Story." Celebration also featured a panel that includes the Star Wars creature design and practical effects team and also debuted a new creature which they nicknamed, "Space Monkey." The creature creation team discussed the meticulous process of designing Star Wars creatures, and how they innovate the use of practical effects, Gizmodo reported.

Rogue One: A Star Wars Story will hit movie theaters in December 16, 2016, while Season 3 of Star Wars Rebels will be back on air some time this coming fall 2016.