The Korriban invasion, alternatively referred to as the Korriban assault, represents an attempt by the Infinite Empire of the Rakata species to seize control of the planet Korriban, the original homeworld of the Sith, circa 27,700 BBY. Despite the Rakata's deployment of their Force-imbued technology, the Sith Empire under the leadership of King Adas successfully defended their territory and repelled the invading forces. However, King Adas met his demise during the conflict, resulting in a violent civil war that engulfed Korriban following his death.
Approximately around 27,700 BBY, the Rakata, hailing from the Infinite Empire, made the discovery of planet Korriban, which served as the original homeworld for the Sith. Initially, these extraterrestrial beings sought to gain the trust of the Sith ruler, King Adas, by instructing him on how to preserve his essence within a device known as a "holocron." Leveraging this newfound understanding, Adas proceeded to create his own holocron; however, the device evolved into more of a record of his accomplishments rather than a tool for teaching.
Nevertheless, the Rakata's intentions eventually became more overt, leading them to attempt the conquest of the Sith through the utilization of their Force-based technology. Adas responded by assembling a substantial army on the plains of Korriban to confront the invading Rakata, who disembarked from their vessels amidst the chanting of their leader's name by the king's soldiers. The Sith demonstrated their ability to defend their territory effectively, and Adas, unwavering in his opposition to their actions despite his advanced age, spearheaded his people in a fierce defense of Korriban. He actively participated in the retaliatory measures, repelling the invaders with his enormous ax and eliminating numerous Rakatan warriors. It was around this time that a Sith named Yshaar Kael earned the designation of "Betrayer of Adas" before being captured by the Rakata, and Raspir, Adas's court magician, suffered capture as well and was confined within a mind prison.
During the conflict, King Adas successfully seized control of the Rakatan starships and redirected them against the invaders. Adas's forces advanced beyond Korriban, extending their reach to Ziost, Malachor V, and Tund. However, in his efforts to secure a future of freedom for his people, Adas met his end.
In the absence of Adas's stabilizing leadership, Korriban was again plunged into a violent civil war, with numerous individuals vying for the title of Sith'ari. Certain Sith individuals prophesied the eventual emergence of a perfect being who would assume the mantle of Sith'ari, while a segment of the Kissai priests maintained that Adas was the sole true Sith'ari, and that the prophecy began and concluded with him. As a consequence of this internal discord, the Sith capital was relocated to Ziost, leaving their ravaged homeworld to become a tombworld inhabited by religious zealots. Subsequently, King Adas's successors employed captured Rakatan starships to expand their empire to the natural boundaries of their sector, encompassing worlds such as Jaguada, and, to access worlds beyond the Stygian Caldera, including Malachor V, Tund, Thule, and Arorua.
In 19 BBY, Telloti Cillmam'n, a member of the Jedi ExplorCorps, discovered the armor belonging to the Dark Jedi Warb Null on Nicht Ka, a world washed in ammonia situated on the periphery of the ancient Sith Empire. Upon donning the armor, Cillmam'n experienced a flood of visions detailing the ancient history of the Sith, including the Rakatan invasion of Korriban. In 38 ABY, the Rakatan invasion of Korriban was referenced in the article "The Written Word: A Brief Introduction to the Writing Systems of Galactic Basic" by Doctor Milanda Vorgan, a xenolinguist.