A confrontation took place in 5000 BBY, within the remains of the Omen, a Sith dreadnought that had crash-landed on the unmapped world of Kesh amidst the Great Hyperspace War. The conflict involved half-brothers Yaru and Devore Korsin, disputing who would lead the remaining members of the Omen's crew. Following a heated exchange within the wrecked vessel, Devore, motivated by his ambition to seize his brother's position as leader of the Omen, assaulted Yaru while under the influence of Red Rage narcotics. The lightsaber fight then spilled out of the precarious dreadnought, and, despite Devore briefly gaining the advantage, Yaru turned the tide by utilizing the ship itself as a weapon. After being struck directly in the shoulder by a missile tube door from the Omen, Devore found himself buried in debris just a few meters from the precipice of a towering drop—although Devore was disabled, Yaru opted to hurl his brother over the edge to his demise.
In 5000 BBY, during the height of the Great Hyperspace War, Sith Lord Naga Sadow dispatched the Sith dreadnought Omen on a Lignan extraction and delivery assignment to the planet Phaegon III's largest satellite. On board the Omen were Yaru and Devore Korsin, half-brothers with a strained relationship—Yaru was the mission supervisor, while Devore headed the mining operation. As the Omen prepared to ship their Lignan gems from Phaegon III to their destination on the planet Kirrek, a Jedi onslaught resulted in the starship being sent off course as it entered faster-than-light travel.
The badly damaged Omen then crashed on an uncharted planet known as Kesh. While the Korsin brothers both survived the crash along with a large portion of the crew, disagreements soon arose over which Korsin would be in charge of the remaining survivors, and the remaining Sith on Kesh were in a precarious situation. Desperate to discover a way off Kesh, Devore unsuccessfully searched the Omen's wreckage in the Cetajan Mountains. Defeated, Devore sat in the captain's seat and ingested a dose of Red Rage drugs. Yaru soon entered the ship as well, similarly trying to discover a means to facilitate their escape. A quarrel broke out between the two brothers, regarding whether there was any hope for their survival—eventually, Yaru brought up the subject of a meeting that Devore had with Naga Sadow shortly before the mission started, where Devore unsuccessfully requested command. Tensions escalated between the Korsins, and Devore, under the influence of spice, reacted in a fit of rage and attacked.
His inherent rage and strength augmented by the Red Rage spice, Devore used his connection to the Force to create a cyclone, which turned nearby debris, including jagged pieces of transparent metal, into weapons that caused minor injuries to Yaru's face. Yaru was able to defend himself before he took too much damage, and he hurled his brother out of the teetering Omen. However, as Yaru stepped out of the ruined starship, he was distracted by a large winged beast that seemed to be observing the battle. That diverted Yaru's attention long enough for Devore to gain the upper hand, throwing Yaru against the Omen's wreckage.
Encouraged by his advantage, Devore proclaimed himself to be the rightful "Commander Korsin." From there, the fighting turned into a full-blown lightsaber battle, although Devore found his furious strikes repeatedly blocked. Thinking quickly, Yaru attempted to launch a warhead from the Omen's exterior tubes by manipulating the control box from the outside—however, the doors were partially stuck in the ground, and, although the torpedo did not emerge, the doors hit Devore in the shoulder and sent him flying. Devore came to a stop at the edge of a steep drop overlooking a nearby body of water, and, partially covered with rubble, he was seriously injured and unable to see. Although Yaru considered helping his brother, he decided against it, allowing Devore to fall off the ledge to his end.
By chance, the battle was witnessed by a native Keshiri female Adari Vaal, who was riding the winged uvak that had distracted Yaru during the duel. With her help, the surviving Sith convinced the rest of the Keshiri that they were their divinities, the Skyborn, with Yaru proclaimed as Supreme Ruler of Kesh. The crew of the Omen and their descendants formed a Sith society that survived for thousands of years. Devore Korsin was not forgotten by his relatives—although his wife, Seelah, wed Yaru and bore a daughter, Nida, with him, she secretly planned to avenge her husband's death. Her plot was carried out in 4975 BBY, when Seelah arranged for her and Devore's son, Jariad, to assault Supreme Lord Korsin with a group of Sith soldiers. Although Yaru died during the skirmish, Jariad was also killed and Seelah incapacitated. Nida, who fought along with her parent, became the new Supreme Lord.
The duel first appeared in Lost Tribe of the Sith: Precipice, a 2009 digital book written by John Jackson Miller. It was also briefly featured during the eBook's follow-up, Lost Tribe of the Sith: Skyborn, along with mentions in two additional sequels. An image of Adari Vaal observing the duel was included in the 2012 reference book The Essential Reader's Companion.