Season 3 of "Star Wars Rebels" is all set to introduce one of the prominent characters from the franchise to the series who will pose a big threat to the Rebel alliance and their missions. Besides it, there will be one more character debuting in Season 3. However, it is not yet revealed which side he will joining.

Grand Admiral Thrawn will appear in the third season as the primary antagonist and one of the major characters. It is surely going to make things more difficult for the Rebels as this time, their greatest threat is a superior and intellectual one. Also, rumours have suggested that Thrawn might form an alliance with the other new character Bendu and together they will try their best to put an end to Rebels' missions.

Several reports have stated that Darth Vader will also return to "Star Wars Rebels" Season 3 from the previous seasons and will play a key role in the upcoming episodes. However, the season will emphasise more on the errands of the new antagonist.

Thrawn was first introduced in "Star Wars" expanded universe which has stopped coming out with new content anymore. Created by Timothy, "Rebels" show-runner Dave Filoni decided to include the character in the animated series as he wanted the Grand Admiral to play a major part in "Rebels." Filoni also stated that another reason why he decided to include Thrawn in Season 3 is because of the artwork and the character's appearance that he liked a lot.

In the meanwhile, several speculations state that Darth Maul will also be returning and will continue to lure Ezra Bridger towards the Dark Side. Maul is still eyeing Ezra to be his Sith apprentice. However, whether Ezra falls in his trap or not, will be seen once Season 2 premieres. Fans are also hoping for a battle between Maul and Vader, but chances are very unlikely as Maul realises how strong and powerful Vader is.

"Star Wars Rebels" Season 3 is all set to air on Sept. 24 on Disney XD.