WARNING: MAJOR Spoilers For Star Wars Rebels Season 1 & Clone Wars animated series!
Star Wars Rebels wrapped up season 1 this past week, tying a big seasonal reveal into some unexpected reunions with beloved characters from the saga's past. Now that our favorite Lothal rebels know they are part of a larger rebellion - and that Anakin Skywalker's former padawan, Ahsoka Tano, is organizing that movement along with Senator Bale Organa - it seems that Rebels will be slowly moving on from its semi-isolated team origin story, in order to form bigger and tighter connections with the larger Star Wars shared universe.
However, as hardcore fans attempt to map out how all the pieces of the canonical Star Wars universe now fit together, there are some mysteries that Rebels left unsolved in season 1 - mysteries that could possibly have great importance to the upcoming new movie installment, Star Wars Episode VII: The Force Awakens.
Of those dangling mysteries, one of the biggest is undoubtedly: Who is (or was) the evil Inquisitor, and what's the story behind both his sect of the Empire, and his knowledge of the Darkside of The Force?
The Old Origin
In the Star Wars Expanded Universe (unofficial novels and other media created independent of George Lucas), The Inquisitors are part of an order known as The Inquisitorius, which was formed by Emperor Palpatine the same year he seized power of the Republic, and converted Anakin Skywalker into Darth Vader. The Inquisitors' job was simple: hunt down and kill any surviving Jedi after "Order 66" and The Great Jedi Purge, while also converting any independent Force-users to the Dark Side under Palpatine's service.
In the line of Expanded Universe novels, The Inquisitors were "Force-sensitive agents" or "truth agents." They were NOT Sith Lords, but were trained in the use of the Dark Side and lightsabers, as well as methods of manipulation and interrogation. Most dangerous of all: The Inquisitors were well-studied on the history, methods, and teachings of the Jedi Order, allowing them to have strategic advantage over their opponents. They were originally based on Coruscant in the old Jedi Temple; later on the planet Prakith. In one EU story, Inquisitors nearly uncover a young Princess Leia's true identity, due to her Force sensitivity.
A New Introduction
Due to the rules of the new Star Wars Shared Universe, the entire history and mythology of The Inquisitors (as described above) no longer counts as official part of the Star Wars saga. Only the events of the Star Wars movie Episodes and spinoffs; the Clone Wars and Rebels animated series; and any new books released from here on out (one so far and counting...) will be branded as official parts of the Star Wars story.
With that understanding: the Star Wars Rebels cartoon series has provided a new introduction to The Inquisitors: From what we know so far, The Inquisitors (thus far represented by a single agent) are much the same as the version presented in the Expanded Universe (not Sith, use Dark Side, lightsabers, interrogation, and knowledge of Jedi studies).
In a special edition of the Rebels pilot, "Spark of Rebellion", we witness the following exchange between The Inquisitor and Darth Vader, hinting that, in the official canon, the formation of The Inquisitors is still something Emperor Palpatine masterminds after "Order 66":
"The Emperor has foreseen a new threat rising against him: the children of the Force. They must not become Jedi.""Yes, Lord Vader.""Hunt down this new enemy, and if they will not serve the Empire, eliminate them along with any surviving Jedi who would train them. This is my master's command."
As of the Rebels season 1 finale, The Inquisitor is presumed dead, having fallen into an exploding engine core. The animated series has yet to reveal a larger organization like The Inquisitorius, but since the one Inquisitor we met is presumably dead, Darth Vader has come on the scene to investigate the enigma that is lone Jedi Kanan and his new Padawan, Ezra.
But with one agent down, that doesn't mean The Inquisitors are out of the picture completely - and if we're right, the next Inquisitor who comes after the Star Wars Rebels could be a ghost from the past...