The Battle of Korriban, also known as the Attack on Korriban or Korriban Incursion, was a battle that occurred in the year 3638 BBY during the Galactic War between the Old Galactic Republic and the True Sith Empire. The Republic's objective in the battle was to retrieve a set of data from the Dark Council's chamber in the Sith Academy on the planet Korriban. The initial assault titled Wave One managed to breach the Valley of the Dark Lords before being halted by the strong Imperial defenses.
The second wave, which consisted of four Republic heroes, reinforced their position, taking out the four key Imperial ground commanders before facing Lord Renning and killing him. They then had to help Republic forces decide whether or not to free the Imperial slaves, as it was not within their mission parameters. They then made their way into the Sith Academy. Inside the Academy, the heroes defeated Sith instructors to unlock the turbolift to the Dark Council Chamber. Once they ascended the turbolift, the heroes fought their way to the Chamber and defeated Darth Soverus. Jedi Commander Jensyn arrived with reinforcements and struck down the Sith, but not before Soverus mentioned an 'old man' having foreseen the conflict. The heroes returned to Colonel Rian Darok and Theron Shan for a mission debriefing, but word of the concurrent Assault on Tython forced them and the majority of the Republic forces to leave the assault to help retake the Jedi planet.
Towards the end of the Cold War, the Galactic Republic managed to drive back their opponents, but both sides suffered huge losses. During the beginning of the Great War, internal disputes of the Sith hierarchy, resulted the death of two members of the Dark Council and the disappearance of the Emperor Vitiate, favored the rise of the Republic troops. To continue to urge the Sith Empire on the defensive, Colonel Rian Darok led his Republic forces to attack Korriban, the ancient homeworld of the Sith. Along with SIS Agent Theron Shan, the son of Satele Shan of the Jedi High Council and Captain Jace Malcom of the Republic Special Forces Division, the colonel found the coordinates of the planet's location and allowed Theron to recruit an Operations Team. However, the plan that Darok secretly pursued was to recover ancient Rakata - Technology from the archives of the Sith Academy. Unknown to the Republic, Darok was a member of Revanites, a secret society within the Sith Empire and the Galactic Republic that adhered to the teaching of the powerful Force-user Revan.
Once the Republic forces orbited the planet, Darok led the attack with the knowledge of the Sith Lord Darth Arkous, a member of the Dark Council. While Darok's forces attacked Korriban, Arkous led his Imperial forces to attack Tython, the ancient homeworld of the Jedi, and claim the Rakata artifacts inside the Jedi Temple. Under the leadership of the Republic team, the Republic forces began their attack on the Lower Wildland, killing four Sith commanders. When they arrived at the Wildland Laboratory, the strike team encountered Lord Renning, who fought the operations team by using his Tuk'ata. After defeating Renning in the battle, the Operations team continued to move further in advance towards the Sith Academy, and eliminate the use of many soldiers and Sith. To get into the chambers of the Dark Council, the Republic forces required several codes that they gained in the fight against multiple masters and overseers of the Academy. Inside the council room, the team came face-to-face with Darth Soverus, a pure-blooded Sith and a member of the Dark Council. Despite his combat power, the powerful Sith Lord was defeated and was killed shortly afterwards by Commander Jensyn.
Meanwhile, Arkous' Imperial task force attacked the Jedi Temple on Tython and engaged Oric Traless, a member of the Jedi Council. While the Republic team went to Tython and destroy the Imperial forces and bring the planet back under Republic rule, the Imperial team traveled to Korriban and retake the planet. First, the team switched from Jedi Master Riilna. Then, they penetrated into the academy and brought the four code fragments, which were required for admission into the Council Chamber. There, the mission team presented the Jedi Jensyn and killed them.
By attacking the Korriban's Sith Academy, the valuable Rakata technology came into the possession of Colonel Darok. Together with the Sith Lord Darth Arkous, who was also a member of the Revanites, they provided important Rakata artifacts after the attack on Tython, and planned the creation of a Infinite Army. With this, the Order of Revan would destroy both the Sith Empire and the Galactic Republic.