Grand Inquisitor, also known as Master of the Inquisitorius, was a title used by the highest-ranking Inquisitor of the Galactic Empire. The Pau’an male and former Jedi Temple Guard known only as the Grand Inquisitor, and sometimes the Inquisitor, held this title, and was ranked above other Inquisitors such as the Fifth Brother, Sixth Brother, Seventh Sister, Eighth Brother, and the Ninth Sister. As Grand Inquisitor, he reported to Darth Vader, a Dark Lord of the Sith, and hunted Jedi who had survived the Great Jedi Purge.

Grand Inquisitor was a rank used within the Galactic Empire, which utilized Inquisitors in order to hunt down and destroy Jedi who had survived the Great Jedi Purge. A Pau’anmale, who was once a Jedi Temple Guard, was known only by the title he held of the Grand Inquisitor. He reported directly to Darth Vader, a Dark Lord of the Sith and apprentice to the Emperor, Darth Sidious. He was ranked higher than other Inquisitors, such as the Second Sister, Fifth Brother, Sixth Brother, Seventh Sister, Eighth Brother, Ninth Sister, and Tenth Brother, all of whom were trained in the arts of the dark side of the Force and lightsaber combat. In order to understand his Jedi opponents, he studied the records of the Jedi Archives from the Imperial Palace—which had previously been the Jedi Temple. This gave him an advantage in combat, as he was able to understand Jedi fighting styles.