A brief conflict erupted over the most substantial satellite orbiting Phaegon III not long before the commencement of the Great Hyperspace War in 5000 BBY. Relin Druur, a Jedi Master, found himself in pursuit of his former Padawan, Saes Rrogon, who had recently succumbed to the dark side of the Force. Druur, accompanied by his new Padawan, Drev Hassin, tracked Rrogon's movements. They discovered his allegiance to Naga Sadow's Sith Empire as a Sith Lord. After communicating this information to Coruscant, they resolved to locate and confront Rrogon. In the meantime, Rrogon had been promoted to Captain of the Sith dreadnaught designated Harbinger. He, together with Captain Yaru Korsin aboard the Omen, were tasked with locating and extracting Lignan, a potent ore imbued with the power of the dark side of the Force, intended for use in the imminent Sith invasion of the galaxy. Their search led them to the largest moon of Phaegon III, which held vast quantities of Lignan, prompting them to begin its extraction.
As the Sith concluded their mining operations, Druur and Hassin entered the star system and launched an attack. Druur infiltrated the Harbinger with the objective of sabotaging its hyperdrive, while Drev engaged ten Blade-class starfighters deployed by the Sith vessels against the Jedi's Infiltrator. However, Rrogon intercepted Druur, leading to a lightsaber duel. Rrogon severed Druur's arm, but the confrontation was abruptly halted by the detonation of the explosives Druur had placed on the hyperdrive, rendering Rrogon incapacitated. Drev, realizing that the Harbinger was still attempting to deliver the Lignan to the Sith Empire, and with his starfighter sustaining multiple hits, made the decision to ram the Harbinger's bridge. Druur attempted to escape in an escape pod, but the Harbinger collided with the Omen just as both vessels jumped into hyperspace. The collision diverted the Omen to the isolated planet Kesh, where its survivors eventually established the Lost Tribe of Sith, while the Harbinger itself journeyed through time to 41 ABY.