The Eighth Brother, a male member of the Inquisitorius, was a Force-sensitive Terrelian Jango Jumper. During the Imperial Era, he was an active pursuer of the burgeoning Rebellion, specifically the rebel cell known as the Spectres. His life came to an end on the planet Malachor during a mission to apprehend the former Sith apprentice Maul; after Kanan Jarrus accidentally damaged the Eighth Brother's lightsaber, the Eighth Brother attempted to escape using it, resulting in his death.
Before assuming the identity of the Eighth Brother, he was once a member of the Jedi Order. Following the transformation of the Galactic Republic into the Galactic Empire, he was recruited into the Inquisitorius, an Imperial organization of Force-sensitive assassins tasked with locating and eliminating Jedi who had survived Order 66. He and his colleagues received training from The Grand Inquisitor at the Inquisitorius Headquarters in The Works. After Darth Sidious showed the Inquisitorius to Vader, Darth Vader took command and continued their training in the ways of the dark side of the Force. The Grand Inquisitor told Eighth Brother and his colleagues that they had two masters, Eighth Brother responded by proclaiming that they only served Sidious, but was soon countered by the Grand Inquisitor who stated that times had changed. Vader continued the Eight Brother and his colleagues's training in the ways of the dark side of the Force. Vader taught him and all the inquisitors in the Works the lesson of loss through harsh methods.
After a sparring session involving Fifth Brother, Seventh Sister, Ninth Sister and Thirteenth Sister in which Darth Vader tested Akaris strength, the Eighth Brother appeared with the Fourth Sister, Sixth Brother, and Tenth Brother to watch Vader defeat Akaris. Later, when the Thirteenth Sister entered the fighting pit at Inquisitorius Headquarters to train, the Eighth Brother was present. The two sparred, and the Thirteenth Sister later commented on his homicidal tendencies, stating that he seemed to be looking for any excuse to kill.
In 14 BBY, the Eighth Brother joined the other Inquisitors in celebrating the successful assassination of Eeth Koth by Darth Vader, Fifth Brother, Thirteenth Sister, and Tualon Yaluna.
Following the death of the Grand Inquisitor at the hands of Jedi Kanan Jarrus and his padawan, Ezra Bridger, the Brother and the other Inquisitors saw "new opportunities" to take his place by hunting down the two Jedi and their crew on their VCX-100, called the Ghost. While the Fifth Brother and Seventh Sister were given the opportunity to hunt the Jedi and their crew when Darth Vader dispatched them on the Emperor's orders, the Eighth Brother was assigned to track down Maul, the former Sith apprentice, known to him only as "the Shadow."
Eventually tracking Maul to the Sith temple on Malachor in 3 BBY, the Brother unexpectedly encountered Jarrus, Bridger, and Ahsoka Tano. After observing them briefly, the Eighth Brother engaged the three in combat. Surprised to find them all wielding lightsabers, he initially believed he was facing three Jedi. Deciding he was outnumbered, he retreated. After the trio separated, Tano and Jarrus located and captured the Eighth Brother, who was unable to escape because Chopper had seized his TIE Advanced v1. In captivity, Tano and Jarrus interrogated the Eighth Brother, inquiring about the number of Inquisitors and his purpose on Malachor. However, the Eighth Brother provided only ambiguous responses, refusing to disclose the exact number of Inquisitors and stating that he was hunting a shadow on Malachor. When Tano and Jarrus were not looking, the Eighth Brother managed to send a covert signal, which was answered by the Fifth Brother and Seventh Sister, with all three attacking Tano and Jarrus. However, the tables were turned on them when Bridger arrived with Maul in tow, the pair of them joining Tano and Jarrus and driving the Inquisitors off.
Fearing that Maul had taken possession of a Sith holocron sought by Darth Vader, the Eighth Brother recklessly pursued the enemy to retrieve it. He attacked Jarrus and Bridger, incapacitating the Jedi Knight before focusing on the apprentice, only to be repelled by Tano and Maul. Joining forces with the Fifth Brother, he then confronted Tano and Jarrus, while the Seventh Sister pursued Bridger and Maul. However, Maul arrived and killed the Fifth Brother, while Jarrus damaged the Eighth Brother's lightsaber. Overwhelmed and outnumbered, the Eighth Brother attempted to escape by using his lightsaber's spinning blades to slow his descent as he leaped from the temple, but the weapon malfunctioned, causing him to fall to his death.
Like the other Inquisitors, the Eighth Brother was deeply committed to serving the Empire and Darth Vader. He was known for his aggressive approach, often rushing into battle while his comrades held back to allow him to weaken the enemy. He was also ruthless and sadistic, displaying a willingness to prolong an enemy's suffering before delivering the final blow. However, his impulsive nature proved to be his downfall, as he chose to rely on his damaged lightsaber to escape when confronted with three skilled opponents simultaneously. According to the Thirteenth Sister, the Eighth Brother was always looking for a reason to kill.
The Eight Brother was Force-sensitive, capable of using the Force to summon his lightsaber from a distance. He possessed considerable skill in lightsaber combat, enabling him to engage Ahsoka Tano in battle; briefly contend with Maul alongside the Seventh Sister before being Force pushed off the temple; and fight Kanan Jarrus on equal terms before his lightsaber was damaged. He also demonstrated proficiency in deflecting blaster fire from his own TIE Advanced v1 and retrieving his lightsaber after throwing it. Furthermore, he was a skilled tracker, as evidenced by his assignment to locate Maul on Malachor. His fighting style bore some resemblance to that of the Seventh Sister, owing to his slender and acrobatic physique. However, he did not appear to be significantly more skilled than his fellow Inquisitors in combat, as demonstrated by his defeats on Malachor, but he needless manage to survive longer than the Fifth Brother and Seventh Sister.
Like most Inquisitors, the Eighth Brother wielded a double-bladed spinning lightsaber. He also piloted a TIE Advanced v1, a TIE Fighter design similar to those used by his colleagues. The Eighth Brother typically utilized both blades in combat, and also employed them to propel himself away from enemies when outmatched. Additionally, his lightsaber possessed the unique ability to transform into a buzz-saw-like weapon that utilized the handle while the blades were deactivated, exposing the emitters. Other equipment the Brother used were a multitude of S-Mine Detonators he kept on his belt. Within easy reach, the Eighth Brother would throw these small explosives toward his enemies. He also wore a suit of black and gray combat armor which bore the insignia of the Galactic Empire. On one of his gauntlets, he could send a distress signal.
The Eighth Brother made his debut in "Twilight of the Apprentice," with Robbie Daymond providing his voice. The Inquisitor's design emphasized a lean and angular physique, with armor inspired by medieval plated armor.