The relationships of the Eighth Brother.
- Main article: Darth Vader
The Eighth Brother served as one of Vader's Dark side adepts, obeying his every command without question. At the bidding of his master, Vader ordered the Brother to hunt down Emperor Palpatine's former Sith apprentice, Maul.
- Main article: Seventh Sister
Not much is known about the Eighth Brother relationship with the Seventh Sister, as they are not seen directly interacting with each other very much. On Malachor, the Eighth Brother called the Seventh Sister and the Fifth Brother for help when he was captured by Kanan and Ahsoka. They answered his call and went to his aid, with the Seventh Sister personally freeing him from his bounds, commenting "an excellent day's hunting" whilst doing so.
- Main article: Fifth Brother
The Eighth Brother and the Fifth Brother worked well together, fighting Kanan and Ahsoka and almost winning. The Fifth Brother and Seventh Sister also answered his distress call and freed him. However, the Fifth Brother and Seventh Sister both had a conversation when he left them alone saying "Let him thin them out," implying that he as well as the Seventh Sister, thought lowly of the Eighth Brother.
- Main article: Ezra Bridger
The Eighth Brother encountered Ezra at Malachor and fought him trying to get the Sith Holocron. Whilst Ezra was a formidable foe, the Inquisitor simply used his double-blade mode to defeat the young Padawan.
- Main article: Kanan Jarrus
Kanan Jarrus and Ahsoka Tano captured the Eighth Brother and interrogated him. Whilst the Inquisitor was not powerful enough to fight both of them at the same time, he was smart enough to be able to call for help without them noticing. Later on, Jarrus proved to be stronger than the Inquisitor, damaging his Lightsaber and effectively defeating the Eighth Brother.
- Main article: Ahsoka Tano
The Eighth Brother fought Ahsoka Tano a few times, both times resulted in the Inquisitor's failure to stop her.
- Main article: Maul
The Eighth Brother was tasked with hunting down Maul, but proved to be no match for the former Sith. When Maul fought all three Inquisitors he beat them all. The Eighth Brother tracked Maul to Malachor but never completed his mission.