The Grand Inquisitor, commonly known simply as the Inquisitor, was the name adopted by a Pau'an male Jedi Knight who turned to the dark side of the Force and became the leader of the Inquisitorius, a band of Jedi hunters who served the Galactic Empire. The Grand Inquisitor was once a Jedi Temple Guard and was involved in the events surrounding the bombing of the Jedi Temple during the Clone Wars, arresting the innocent and later exonerated Padawan Ahsoka Tano as well as the true culprit, Barriss Offee. After his fall to the dark side, the Grand Inquisitor was responsible for hunting down and eliminating Jedi during the Jedi Purge. He personally served the Sith Lord Darth Vader, from whom he received his orders, and was intimately familiar with the records of the Jedi Temple.

Although he was a physical opponent for Jedi and tapped into the dark side of the Force, he did not appear overly emotional, instead operating as a cold and analytical mind. Whatever intensity he showed was a result of his purpose in completing his mission.

The Grand Inquisitor also supported Captain Piers Roddance's view that the Empire needed to purge itself of all weakness and regarded compassion as the most insidious weakness.

He should sound like his voice actor, Jason Isaacs, from Star Wars: Rebels.