Darth Arkous, a male Sith and Dark Lord of the Sith, held a position on the Dark Council that governed the Sith Empire during the Galactic War against the Galactic Republic. Having fought in the Great Galactic War, and a dedicated loyalist to the Empire, Arkous masterminded the Assault on Tython. However, the attack on Tython was later revealed to be motivated by Arkous's secret objective: acquiring a Rakata artifact. Following the Korriban Incursion, Arkous reportedly showed interest in a shipment of Isotope-5 originating from Makeb.
In the year 3637 BBY, Darth Arkous called upon an Imperial strike team to aid in the Empire's assault on Tython, publicly stating that it would severely weaken the Republic and the Jedi Order. However, his true intention was to have Lord Goh retrieve Rakata technology hidden within the Jedi Temple. The attack on Tython was timed to coincide with Colonel Rian Darok's attack on Korriban, another location concealing Rakata technology. Upon learning of the attack, Arkous dispatched the strike team to reclaim Korriban to maintain appearances, while the Republic simultaneously retook Tython. Arkous's attempts to contact Goh were unsuccessful, as he discovered that a Republic strike team had eliminated him. After the recapture of Korriban, Arkous commended the Imperial heroes.
Later, Arkous met with Darok on Manaan. Together, they traveled to an underwater facility to consult with a Selkath geneticist named Gorima, seeking a method to integrate Rakata technology into test subjects, creating invincible supersoldiers for the Order of Revan. However, Arkous's former assistant, Lana Beniko, in collaboration with SIS agent Theron Shan, dispatched a strike team to intercept them. Arkous and Darok observed from an observation room as Gorima was confronted. With Gorima's experiments successfully rendering the grafting procedure non-lethal, the two conspirators escaped, setting a depth charge to destroy the facility and eliminate their pursuers, unaware that Shan was present to rescue them before the facility imploded.
Arkous subsequently sent a coded message to Lana, revealing his initial plan to recruit her into the Revanites, but his plans shifted when she found her new allies. He cautioned her against interfering with his scheme, cryptically asserting that the Revanites were everywhere. Lana and Shan tracked Arkous and Darok to Lehon (also known as "Rakata Prime"), the former capital of the Rakatan Infinite Empire, where the Revanites had recovered components of the destroyed Star Forge for Gorima to further his experiments in creating an "Infinite Army." The Republic and Imperial pursuers, joined by the vengeful Wookiee smuggler Jakarro and his protocol droid companion C2-D4, confronted Arkous and Darok on the roof of the Temple of the Ancients, ultimately killing them, despite Shan's desire to capture them alive for interrogation. However, it soon became apparent that neither Arkous nor Darok were the leaders of the Revanites, but rather followers of the true master of the Order of Revan. This master was later revealed to be Revan himself.
Lana Beniko was branded a traitor to the Empire and accused of murdering Arkous, an accusation she couldn't refute due to the Revanites' influence, forcing her to go into hiding with Shan and Jakarro.
Darth Arkous possessed remarkable power as a Dark Lord of the Sith. He was notably skilled in lightsaber combat, and he could use Force choke.
Furthermore, Darth Arkous demonstrated the ability to use telekinesis and displayed proficiency in wielding Force lightning.
Arkous's debut occurred in Game Update 2.7: Invasion of the 2011 massively-multiplayer online roleplaying video game Star Wars: The Old Republic. BioWare released the update on April 8, 2014.
Arkous played a significant role in the Imperial storyline of the "Forged Alliances" story arc, serving as a prelude to the main narrative of the 2014 Shadow of Revan digital expansion. He reappeared in subsequent installments of the story arc, including the "Depths of Manaan" flashpoint introduced in Game Update 2.9: Galactic Strongholds Early Access, which was released on August 19, 2014.
Arkous's final appearance was in Game Update 2.10: Forged Alliances, released on September 9, 2014. He, alongside Darok, his counterpart in the Republic Forged Alliances story arc, served as the final boss encounter for the "Legacy of the Rakata" flashpoint introduced in the update.
After completing the "Korriban Incursion" flashpoint, Imperial players of any gender have the option to flirt with Arkous, suggesting they "take some time to mark the occasion" of repelling Republic forces from Korriban. Arkous declines the player's advances, citing his busy schedule. No further opportunities arise to pursue a romantic relationship with Arkous within the game.