Inquisitor was a rank used within the Inquisitorius Program of the Galactic Empire. As high-ranking members of the Empire, their main purview was to hunt surviving Jedi in the aftermath of Order 66 for the purpose of elimination or induction into the Inquisitorius, where they could be made to serve Emperor Palpatine as agents of the dark side.

The Grand Inquisitor led the Inquisitors. Among the Inquisitors ranks were Brothers and Sisters, the Second Sister, Third Brother, Third Sister, Fourth Sister, Fifth Brother, Sixth Brother, Seventh Sister, Eighth Brother, Ninth Sister, and Tenth Brother. A female, a red-skinned individual, and a Twi’lek, also served as Inquisitors.

The rank of Inquisitor was active by 19 BBY in the aftermath of the Order 66. Fearing the threat that the surviving Jedi posed to his rule, Emperor Palpatine created the Inquisitorius to track down and corrupt or eliminate the last remaining Jedi. The Emperor then tasked his Sith apprentice, Darth Vader, with training the former Jedi in the dark side to become Inquisitors in their service. The Inquisitors were led by the the Grand Inquisitor, who had been personally chosen by the Emperor and came to work alongside Vader. As Dark Lord of the Sith, Vader governed the Inquisitorius in the name of his master, Emperor Palpatine.

In 14 BBY, the Second Sister and Ninth Sister hunted down the Padawan survivor Cal Kestis and his crew on the Stinger Mantis. The Second Sister took a personal interest in Kestis, as she used him to find Eno Cordova’s holocron, which contained a copy of a list of Force-sensitive children made during the final days of the Jedi Order, in an effort win the favor of Emperor Palpatine. Both the Second Sister and Ninth Sister were ultimately defeat by Cal Kestis, with the former having a change of faith after her former Jedi Master, Cere Junda, apologized for her role in her transformation as an Inquisitor. With Darth Vader perceiving her change of faith as failure, she was executed by the Dark Lord.

Blaise Zirkonn, a Force-sensitive agent of the Inquisitorius who worked with the organization for nearly a decade, hoped to be promoted to the rank of Inquisitor. In 4 BBY, after the death of the Grand Inquisitor, the Seventh Sister became a vital commander within the ranks of Inquisitorius. She and other Inquisitors sought to ultimately replace their previous leader as the new Grand Inquisitor, though she was ultimately killed alongside the Fifth Brother and the Eighth Brother.

Eventually, the Empire came to consider the Jedi to be finally extinct, and the Inquisitorius were said to have vanished with them. By around the time of the Battle of Yavin, Vader was considered to be the last of the Jedi religion left in the Empire.