Darth Nyriss, a female Pureblood and a Dark Lord of the Sith, served on the Dark Council for a period exceeding two decades, making her tenure the third-longest at that point in time.
Nyriss, a woman of exceptional power and ambition, was a female Sith Pureblood. Within the Sith Empire of her era, Darth Nyriss stood as a figure of considerable talent and influence. Her triumphs included the conquest of Drezzi, the destruction of Melldia, and her ascension to the Empire's Dark Council, a position earned through her own capabilities. However, the Dark Council of that time was plagued by intense internal rivalries and conspiracies. Nyriss, in particular, became the target of multiple attempts on her life. Consequently, the Sith Emperor advised Nyriss to temporarily withdraw from the Council's political machinations until the situation stabilized. During this period, she took refuge in a heavily fortified citadel situated on the western outskirts of Kaas City. The Sith Emperor also suggested that Nyriss enlist an agent who was not entangled in the Council's politics to aid in her investigation of these events. Nevertheless, Nyriss harbored her own schemes, which she initiated upon the arrival of Lord Scourge, a renowned warrior, on Dromund Kaas to assist her.
By the time Nyriss and Scourge crossed paths, her physical appearance had undergone significant deterioration due to her deep involvement in potent dark side rituals. She was highly skilled in the arts of Sith sorcery and possessed a strong connection to the dark side of the Force. Although Nyriss had once been remarkably beautiful and could have easily afforded the procedures necessary to maintain her youthful looks, she deliberately chose not to, possibly to demonstrate her power in the dark side or to signify her indifference to superficial appearances.
Nyriss's ambitions extended beyond merely eliminating the enemies who sought her demise; she was among the Dark Council members who conspired to overthrow the Sith Emperor. When Scourge discovered this plot, he confronted Nyriss to determine her true motivations. However, Nyriss still valued his usefulness and revealed some disturbing secrets about the Sith Emperor to Scourge in an attempt to secure his loyalty. She even escorted Scourge to Nathema—the Sith Emperor's former homeworld—to substantiate her claims.
Nyriss was the one responsible for Revan's capture on Nathema and held him captive within her stronghold for several years, until the Jedi Master successfully turned Scourge against her by leveraging his talents and teachings. By this point, Scourge was not only prepared to eliminate Nyriss from the equation but was also willing to assist Revan in his plan to assassinate the Sith Emperor. As part of this strategy, Scourge exposed Nyriss's treachery to the Sith Emperor, who then resolved to eliminate all potential threats to his reign with utmost urgency. Shortly thereafter, the Sith Emperor's forces launched an assault and seized Nyriss's stronghold.
As the battle raged on, Nyriss made her way toward the prison cell where Revan was being held. Approaching the stairs that led to the prison cell, she noticed a droid named T3-M4 who alerted others to her presence. In response, Nyriss unleashed a blast of power which sent T3-M4 tumbling down the stairs. Subsequently, Nyriss observed two guards approaching her position, whom she struck with a potent burst of purple lightning. The lethal bolts instantly reduced those unfortunate guards to charred, smoking remains. As Nyriss neared Revan's cell, she detected the presence of another powerful Jedi named Meetra Surik in the room, along with Scourge. Nyriss questioned Scourge about his motives, but upon receiving no answer, she realized his betrayal and attacked him and the Jedi simultaneously. Neither Scourge nor Surik could withstand Nyriss's might. Through a combination of her impressive speed, lightsaber skills, and dark side power, Nyriss subdued both of her formidable opponents concurrently.
Nyriss then paused to prepare for the final blow, as the air around her began to crackle and intensify in heat. While she boasted about her past achievements, Revan emerged from his cell, his Jedi robe pulled over his head and his mask concealing his face. Nyriss unleashed a swirling storm of pure dark side energy to obliterate her adversaries. Revan extended his hands and absorbed the deadly power of the dark side. Revan taunted Nyriss and redirected her power back at her. Nyriss was consumed by her own power and was unable to prevent the lethal bolts from tearing her apart, reducing her to a pile of ash.
Darth Nyriss was a master of Force lightning, which she favored extensively. She was also an expert in Sith rituals, making her a specialist in the field. Furthermore, she was capable of employing Telekinesis, Force speed, and force shield to defend herself from attacks. Nyriss demonstrated exceptional combat prowess, subduing both Lord Scourge and Meetra Surik. Darth Nyriss practiced Juyo in lightsaber combat and wielded a standard red-bladed lightsaber.
Darth Nyriss made her debut in the novel The Old Republic: Revan by Drew Karpyshyn. In the 2012 reference guide The Essential Reader's Companion, Darth Nyriss's name is consistently misspelled as Darth Nyris.