The Grand Inquisitor

The Inquisitor is the currently unnamed antagonist in the upcoming television series Star Wars: Rebels. Five years before the first Star Wars movie, A New Hope, The Inquisitor was tasked with the job to seek out and assassinate any remaining Jedi in the galaxy. The one who gave him such a task is none other than the Supreme Imperial Commander Darth Vader.

Biography
The nameless Inquisitor, as aforementioned, serves the Galactic Empire, specifically its second most powerful entity, Darth Vader. However, the alien Pau'an assassin directly serves the Imperial subdivision, The Inquistorius, one of the most high ranking divisions of the Empire that fulfill the missions given to them by the two sith lords, Darth Vader and Emperor Palpatine. After his employment into the unit, he was tasked to execute any Jedi he discovered with an endless army of Stormtroopers under his command.

Star Wars: Rebels
The Inquisitor will serve as the main antagonist in the upcoming TV series Star Wars Rebels.

Trivia

 * The Inquisitor will serve as the main antagonist in the upcoming film, Star Wars Episode VII, set to premiere in 2015.