Backstory:

The Grand Inquisitor was the title 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 Great Jedi Purge. Selected by the Emperor, Darth Sidious himself, for the position of Grand Inquisitor, he personally served the Dark Lord of the Sith, Darth Vader, from whom he received his orders. Throughout his tenure he proved to be one of the regime's most proficient tools in eradicating the last of the Jedi Order, being intimately familiar with the records of the Jedi Temple.

The events with Offee and Tano left the future Grand Inquisitor feeling disaffected, and he lost faith in the Jedi Order. This left him susceptible to the pull of the dark side of the Force, and ultimately fell to the dark side. However, the Pau'an was still a Jedi by the time the Clone Wars ended, as he was a survivor of Order 66.

At the end of the war, the Supreme Chancellor—secretly the Dark Lord of the Sith Darth Sidious—transformed the Republic into the Galactic Empire and declared himself Emperor of the galaxy. During this time, the Emperor recruited him to become Grand Inquisitor of the Inquisitorius when he promised the Jedi Knight the chance to read through the secrets of the Jedi Archives.

When We See Him:

The Inquisitor came into the service of the Empire and the Sith, though he was not a Sith himself. When the Inquisitor entered the Jedi Temple's Archives, he was confronted by the Sith Lord Darth Vader, who was once Anakin Skywalker before his own fall to the dark side. He and the cyborg then fought each other until the latter damaged his lightsaber. The fight was then stopped by the Emperor, who explained to Lord Vader who the Inquisitor and the Inquisitorius were. They then went to the Inquisitorius Headquarters in The Works to meet with the other Inquisitors.

Vader then tasked the Inquisitor with hunting down and eliminating any Jedi who had survived Order 66, the order given to the clone troopers of the Grand Army of the Republic to destroy the Jedi Order. To accomplish this task, the Inquisitor was trained in the ways of the dark side and studied the records of the Jedi Temple in order to better know his enemies. Seeing how his new master employed brutal training methods that resulted in the loss of limbs from various of his Inquisitors, the Grand Inquisitor questioned Vader's methods, but the Sith Lord responded by saying that he was teaching loss to the Inquisitors and that they still fought like Jedi. After some arguing, The Grand Inquisitor reminded Vader the if the Inquisitors were to fail, said failure would be reflected on him as the Emperor appointed him to train them.

Pau’an

Male

1.98 meters 

Yellow (dark side)

Ashen White (With Red Markings)

His Voice:

For The Grand Inquisitor, I want you to capture the essence of the original voice by Jason Issacs. A low bass tone with a British accent. 

Here are links to some YouTube videos featuring the original voice of The Grand Inquisitor (Voiced By Jason Issacs)