Darth Aruk held the title of Dark Lord of the Sith and served on the Dark Council of the reconstituted Sith Empire during the era known as the Cold War with the opposing Galactic Republic. As a Dark Council member, Aruk oversaw the Sphere of Sith Philosophy, making him responsible for both upholding the tenets of the Sith Code and disseminating anti-Jedi propaganda throughout the Empire. Furthermore, this Sith Lord worked to eliminate Revanite followers, whom he saw as corrupting the pure nature of the Sith with their heretical beliefs regarding Darth Revan's philosophy of balance within the Force.
By the year 3630 BBY, it was assumed that Aruk, or perhaps a successor bearing the same title on the Dark Council, had met their death. This assumption stemmed from the belief that Darth Vowrawn, alongside Empress Darth Acina, were the only surviving members of the Dark Council. Acina later restructured the Council, reducing it to five seats and incorporating the Sphere of Sith Philosophy into the broader Sphere of Sith Doctrine.
The character of Darth Aruk was initially introduced in Star Wars: The Old Republic Encyclopedia, a companion book for the BioWare video game Star Wars: The Old Republic. The reference guide was released by Dorling Kindersley on October 15, 2012. Notably, Aruk stands out as the sole Council member mentioned in the Encyclopedia who does not make an appearance in Star Wars: The Old Republic, with the exception of Darth Rictus, who was introduced a month later in the novel The Old Republic: Annihilation, penned by Drew Karpyshyn and published on November 13, 2012.