The Inquisitorius, also known as the Inquisitorius Program, the Order of Inquisitors, and the Imperial Inquisition, was an organization of mysterious, Force-sensitive dark side agents who served the Sith-ruled Galactic Empire. Members of the Inquisitorius were called Imperial Inquisitors, or simply Inquisitors, and were also nicknamed “Red Blades.” They were tasked with hunting down the remaining Jedi who had survived Order 66 at the end of the Clone Wars as part of the Great Jedi Purge, as well as other political dissidents, and retrieving any children identified as Force-sensitive. The Inquisitors were governed by the Sith Lord Darth Vader, who was the apprentice to the Galactic Emperor, Sheev Palpatine, and led by an individual known only by his title, the Grand Inquisitor.
In the years leading up to the Galactic Civil War, the Inquisitors came into conflict with several Jedi and groups affiliated with surviving or former Jedi as part of the purge. One of these groups were the Spectres, a rebel cell that included the Jedi Purge survivor Kanan Jarrus and his Padawan, Ezra Bridger. Their pursuit of the Spectres also brought them into contact with another Jedi Purge survivor, the former Jedi Ahsoka Tano, as well as the former Sith Lord Maul, who sought revenge against the Sith for casting him out and killing his brother and mother. When the Empire believed the Jedi Order to be largely extinct by the time of the Galactic Civil War, the Inquisitorius were said to have vanished.
Where are the Inquisitors during the time of the original trilogy and the Galactic Civil War? As far as we know right now, they’re all dead! When the Jedi Order fell we know of at least ten Inquisitors. But over the course of nineteen years they were killed by the Jedi they hunted, their own, mind-tricked purge troopers, or even Darth Vader himself. The final known Inquisitors were the Fifth Brother, Seventh Sister, and Eighth Brother, all of whom died on the planet Malachor.