The faction known as the Korsinite League constituted a political group within the Lost Tribe of Sith on the planet Kesh. Their existence coincided with the tumultuous era referred to as the Time of the Rot. The Korsinites held in high esteem Yaru Korsin, the Tribe's founder and inaugural Grand Lord, along with his daughter Nida Korsin, considering them divine figures and striving to emulate their lives entirely. The Testament of Yaru Korsin was regarded by them as a sacred scripture, and they branded their adversaries as "heretics" and "defilers," believing they were desecrating the Tribe, the very essence of Yaru, and thus merited annihilation. By the year 3000 BBY, the Korsinite League had fallen under the command of Korsin Bentado, who later participated in the pivotal Pantheon's Peace that same year. During that year's Testament Day, the leaders of the Sith factions discovered that the Tribe's forebears had actually been slaves serving the Sith Lord Naga Sadow, debunking their perceived "special" status. This revelation of the Tribe's "shameful history" ignited a chain of fierce uprisings known as the Great Crisis, during which the various factions clashed before dissolving into individual Sith conflicts.
Subsequently, Korsin allied with former adversaries, including Edell Vrai, the mathematician from the Golden Destiny, and Neera, the leader of Force 57, with the aim of obliterating the Omen, the ancient Sith starship responsible for transporting the Tribe's ancestors to Kesh. Their intention was to eradicate the last vestige of the Tribe's dishonorable past. However, Varner Hilts, the Caretaker and historian, intervened, thwarting the Sith's plan by unveiling a map that revealed the existence of another continent named Alanciar. Consequently, the Sith factions ceased their infighting and elected Hilts as their new Grand Lord, thereby bringing an end to the Time of the Rot. Bentado and his fellow Korsinites also submitted to Hilts, whom they admired for restoring their faith in Korsin. During the period known as the Hilts Restoration, Bentado ascended to the position of High Lord, while many of his adherents enlisted in the Ebon Fleet, a squadron of airships utilized to invade Alanciar.
The Korsinite League held the revered opinion that Yaru Korsin, the originator of the Lost Tribe of Sith, and his daughter Nida Korsin were divine beings, and they worshipped them. They firmly believed that the first Grand Lord came from beyond, and that the Tribe itself was the embodiment of the leader. Furthermore, the Korsinites also maintained that anyone who endangered the body deserved neither compassion nor continued existence. They also considered the Testament of Yaru Korsin as a sacred text outlining the Tribe's power structure, which had to be strictly adhered to. As a consequence, the Korsinites regarded Testament Day, a holiday observed every twenty-five years to commemorate Korsin's legacy, as a "grand and celestial time" that celebrated the lives of Yaru and Nida. Due to their unyielding and dogmatic adherence to tradition, the Korsinites were unwilling to accept a public reading of the Testament on any day other than the designated anniversary.
The Korsinite League was established by a former slave, approximately a century prior to 3000 BBY. This individual adopted Korsin as a title for himself, distinct from the hierarchy of Lords, and modeled his life after those of the first Grand Lord Yaru Korsin and his successor daughter Nida Korsin. Furthermore, this individual proclaimed that any worthy Sith could aspire to a state of "Korsin-ness". His followers decided they could also adopt the title for themselves, which the movement's founder opposed, but it continued well after his death. Consequently, all members of the cult had Korsin as their first name and also wore black uniforms. Some even donned uvak-leather garb which resembled those worn by members of the Skyborn Rangers, the Tribe's aerial force which had been founded by Nida Korsin.
By 3000 BBY, there existed hundreds of Korsins of both sexes, who would recite mantras and proclaim their empires of one to anyone within earshot. According to Varner Hilts, the Caretaker and historian, engaging in conversation with a member of the Korsinite League was "to risk death by cognitive dissonance." Their rivals during the Time of the Rot included the Sisters of Seelah, Force 57, and the Golden Destiny. In that same year, Korsin Bentado and the League journeyed to the Sith capital Tahv upon learning that Iliana Merko, the leader of the Sisters, was attempting to manipulate the Testament of Yaru Korsin prior to Testament Day. During that very Testament Day, the assembled Sith factions unearthed an earlier recording beneath Yaru Korsin's Testament, revealing that the Lost Tribe's early ancestors were, in fact, slaves of the Sith Lord Naga Sadow. This revelation overturned the Tribe's cherished mythology that their ancestors had been great conquerors.
This revelation ignited a series of violent riots and killings known as the Great Crisis, which devastated much of Keshtah Minor. The Korsinite League clashed with their rivals before descending into infighting themselves. During the Crisis, Bentado lost his hand to Merko and vowed vengeance against the Sith woman. Later, Bentado joined forces with the surviving members of the Sith factions including the Force 57 leader Neera and Golden Destiny member Edell Vrai to destroy the ancient starship Omen in an attempt to destroy the "inglorious" heritage of the Sith. They were stopped by Caretaker Varner Hilts who revealed the existence of a second continent known as Alanciar. Hilts urged the Sith to commit themselves to reaching and conquering this new continent. Hilts was subsequently appointed as Grand Lord by the other Sith factions including the Korsinite League.
While many of the various Sith factions were dissolved during the Hilts Restoration, many former members of the Korsinite League still gravitated around Korsin Bentado, who had become a High Lord in Hilt's government. He was designated as the leader of the invasion force that would invade Alanciar. At the behest of Grand Consort Iliana Hilts, Grand Lord Hilts had appointed Bentado as High Lord in order to give the Korsinite leader something to do besides starting cults around Korsin. In addition, the Grand Lord also assigned the Keshiri servant Squab to work with Bentado. In reality, Squab was a spy who was loyal to Iliana. Meanwhile, Edell Vrai was appointed as the chief engineer for developing airships that would allow the Tribe to reach Alanciar. Edell made an agreement with Bentado to only launch the invasion after the former had returned from a scouting mission to Alanciar.
In 2975 BBY, Edell made contact with the Alanciari but his airships were attacked and shot down by the natives. However, he and five other crew members survived and these succeeded in capturing the Alanciari trawler Mischance, which they used to return to Keshtah. In addition, they also captured two Alanciari: the signal officer Jogan Halder and the Wardmaster Quarra Thayn. Edell's crew returned to Keshtah by ship while he and Quarra embarked on a reconnaissance mission of Alanciar. Despite the Tribe's poor intelligence on Alanciar, Bentado insisted on invading the continent because he believed that Edell had failed since he was a tinkerer and not a warrior. Hilts reluctantly allowed Bentado and his invasion force the Ebon Fleet, which contained sixty airships, to depart for Alanciar. The Ebon Fleet was staffed by many Korsinite League members but included a large complement of Keshiri servants including Squab, who were loyal to Grand Lord Hilts.
While Hilts later learnt about the military capabilities of the Alanciari from Edell, he did not share this information with Korsinite League because he intended to annihilate Bentado and his supporters, who he and Iliana viewed as a threat to his rule. As a result, many of the Korsinite League were killed when the Alanciari Keshiri shot down the Tribe's airships with ballistae at the Western Shield. However, Bentado and the crew of his personal dirigible Yaru survived the massacre and managed to escape the battlefield to Sus'mintri, the capital of Alanciar. There, they managed to infiltrate Vaal Hall, the headquarters of the War Cabinet, at night and kill the entire Alanciari government. They also seized control of the building's strategically important signal tower and the "Worldwatch", a situation room which controlled all signals and telepathic communications on Alanciar.
Having realized Alanciar's full military and industrial potential, Bentado then conspired to mutiny against his Grand Lord and create a "Second Tribe" on Alanciar. He intended to rule the continent from behind the scenes by using Vaal Hall to command the Alanciari military, semaphore stations, and thoughtcriers. To carry out his plans, he intended to use the Alanciari ballista to shoot down Hilts' flagship Good Omen. However, he was opposed by Edell Vrai, who was loyal to Grand Lord Hilts, and Quarra Thayn, who condemned Bentado for murdering the War Cabinet. Following a brief lightsaber duel with Edell, Bentado was killed by Squab under the orders of Grand Lord Hilts, who had learnt about Bentado's mutiny. Squab then handed command of Vaal Hall over to Edell who then reasserted control over Bentado's men and the signaling devices.
Following the death of Bentado, the surviving members of the Korsinite League, who had accompanied Bentado to Vaal Hall were disarmed by Edell and the Keshiri servants, including Squab, who had accompanied Bentado. These Keshiri slaves were loyal to Grand Lord Hilts and quickly cooperated with Vrai. Edell was able to force the Korsinites to yield to his authority by threatening to bring all of the Alanciari down upon Vaal Hall if they did not surrender. Edell also communicated a deal from Grand Lord Hilts to the surviving Korsinities. Grand Lord Hilts intended to exile or enslave the defeated Korsinities. Due to their heavy losses at the Western Shield and the death of their leader, the Korsinite League was broken. During a public gathering, Hilts and his new "ambassador" Jogan Halder claimed that the Tribe were the benevolent Protectors, gods in Keshiri religion. Meanwhile, Bentado and the Korsinite League were depicted as "servants of the Destructors" who had been expelled from the Tribe for their troublesome ways. Following the unification of Alanciar and Keshtah, the surviving Korsinite League supporters were taken into custody and enslaved by Hilt's forces.