Cold War (Galactic Republic–Sith Empire)

The terms of the punitive Treaty of Coruscant called for an immediate cease-fire and the withdrawal of all Republic and Jedi forces from battlefields across the galaxy. As the Treaty went into effect, worlds once allied with the Republic were left defenseless and were quickly absorbed by the Empire. Other planets, angered by the Senate acceptance of the treaty, decided to separate themselves from the Republic.

As the Jedi returned to their ruined temple on Coruscant, they were met by anger on the part of the Senate, who placed blame for the war at the feet of the Jedi Order. The Jedi—unable to stay on Coruscant, where public opinion had turned against them—relocated to the world of their origin, Tython.

Although his Empire was stronger than ever, the Sith Emperor no longer seemed to desire total conquest. He handed over control of the Empire to the Dark Council, a body of twelve Sith Lords who would oversee the day-to-day affairs of state. The Dark Lord went on to pursue his own mysterious goals as the Sith consolidated their power.

Border skirmishes and proxy wars between the Empire and Republic erupted, and the uneasy truce between the two foes appeared to be on the verge of collapse. The conflict included small battles in the Outer Rim and other conflicts fought by proxy. One such conflict was the Separatist War on Ord Mantell, a civil war between the corrupt planetary government that remained loyal to the Republic and a guerrilla force wishing to secede.

During the Cold War, Kel Dor Jedi Master Gnost-Dural made a of the events surrounding the treaty at the behest of the Jedi Council on Tython.

Near the end of the Cold War, both the Republic and Empire gained four new, powerful heroes. On Tython, two incredibly talented apprentices, a Consular and a Knight, arrived and were trained, both becoming notable participants of the war and contributing greatly to the Republic.

The Consular began by saving the Tythonian Forge from destruction at the hands of Nalen Raloch, and successfully gathered three of four holocrons, and found the Fount of Rajivari, which contained the contents of the fourth holocron, and more. The Consular then saved the Jedi Order from internal destruction by learning an ancient shielding technique when several Jedi Masters became infected by an ancient, dark plague. Successfully learning the technique, the Consular healed the afflicted masters and tracked the plaguemaster to a lone flagship. The plaguemaster, Lord Vivicar was defeated, and the spirit of Terrak Morrhage was expelled from his body. The Consular was then named the third Barsen'thor in the history of the Jedi Order.

The Knight first began helping the Jedi Order by defeating the Flesh Raiders and two Dark Jedi, Callef and Bengel Morr, who were responsible for controlling the Flesh Raiders during the events of the Flesh Raider uprising. The Jedi Knight then followed up with victories against the Sith, pursuing enemies across the galaxy, such as Tarnis, a Sith Lord under the disguise of a doctor. When Tarnis was slain, his father, Darth Angral, bore a personal grudge against the Knight during the resulting Desolator crisis. When Angral decided to unleash a powerful superweapon on Tython in order to destroy it, the Knight was responsible for defeating Angral, destroying the Desolator and protecting Tython. Due to this, the Knight earned the title "Hero of Tython."

Simultaneously, a trooper was assigned to Havoc Squad on Ord Mantell. Havoc Squad's commander, Harron Tavus, soon betrayed the Republic and defected with the rest of Havoc Squad except for the new trooper. As the only remaining member of Havoc Squad, this trooper became the new commander and was assigned to track down the traitors while the squad was rebuilt.

A smuggler also arrived on Ord Mantell, delivering a shipment of weapons. The smuggler was immediately betrayed by Skavak and was accidentally involved in the hunt for the lost treasure of Nok Drayen, the legendary pirate and thief. The smuggler eventually claimed Nok's reliquary for themselves and, with Risha Drayen, went on to become a legend in the criminal underworld. Working as a privateer for the Republic, the smuggler eventually exposed Imperial agents in the Senate and defeated the Imperial admiral known as the Voidwolf. By accomplishing that, they gained the name "Voidhound" and claimed a massive pirate fleet and criminal empire, continuing to support the Republic.

At the same time that the heroes of the Republic came to light, four other exceptional individuals aligned with the Empire. Two of them, one a former slave and another a Sith Acolyte, were sent to Korriban and taken under the wings of Darth Zash and Darth Baras, respectively.

The slave was sent into the dark pits of the tombs on Korriban to prove themselves worthy of being Sith. All the while, they dodged several attempts on their life by their overseer, Harkun. After gaining their apprenticeship, they went on to become a powerful Sith Inquisitor and recovered the ancient relics of Tulak Hord. At the same time, they fought many battles for the Empire across the galaxy. After defeating their master, Zash, they were named a Lord of the Sith. They were given the name Lord Kallig, and established their own power base within the Sith Order and Imperial society.

Meanwhile, the other became a potent Sith Warrior. They served their master in combating his nemesis, Jedi Master Nomen Karr, and tracking down his padawan. They traveled across the Empire and saved their master's network of spies across Republic and Hutt Space. They succeeded in bringing down many Republic allies and Jedi in their mission. After defeating Nomen Kaar, they were rewarded with the title of Sith Lord and went on to serve their master against the Republic and Jedi.

The other two, the Imperial agent Cipher Nine and an unidentified bounty hunter, appeared on Nal Hutta, the former working on a mission to secure Hutt support for the Empire, and the latter to gain sponsorship in the Great Hunt. Cipher Nine gained the title of Cipher after performing successful missions for Imperial Intelligence. After they departed Dromund Kaas, they spent the Cold War tracking down and eliminating terrorists in the Empire. After defeating all the terrorist cells and their leader, they secured the Empire against further internal attacks and gained prestige. Meanwhile, the bounty hunter became engaged in a bitter contest across the galaxy. All the while, they battled the attempts by a dishonorable Mandalorian named Tarro Blood to sabotage them. After killing Tarro and the Jedi Kellian Jarro, they were named the Grand Champion of the Great Hunt and were welcomed into the Mandalorians by Mandalore himself.

The outbreak of a new war between the Empire and Republic was preceded by a number of proxy clashes, among them the conclusion of several conflicts which had been left unresolved at the close of the previous war between the two great powers.

With the end of the last war, the Empire declared victory in their long struggle for control of the industry world Balmorra. Ultimately, however, the celebration proved to be premature. Elements within the Republic Army refused to cede defeat, choosing instead to defy the Treaty of Coruscant by remaining on Balmorra and forming a resistance movement in partnership with the planet's natives. After over a decade of guerrilla warfare, Republic interests finally prevailed when a Jedi Consular rallied the resistance and drove the Empire from the planet.

Meanwhile, in the Outer Rim, the Empire scored a victory of its own. For a number of years during the , the Republic had made an effort to turn the ruined world Taris into a symbol of hope, by rebuilding the planet following its devastation at the hands of the Sith three centuries earlier, during the Jedi Civil War. The Republic's efforts would ultimately prove fruitless, as Darth Gravus spearheaded an effort to sabotage the project by eliminating key supporting personnel. With their deaths, the project collapsed and the Republic's work to restore the planet came to an end. Even as they were being driven from Balmorra, the Empire was able to claim victory on Taris.

During the strain on the tenuous peace, Republic Navy Fleet Admiral and Jedi Master Oteg was contacted by the spirit of the long-dead Jedi Master Meetra Surik. Having vanished from Republic space three centuries earlier, Surik had died in a failed attempt to slay the Sith Emperor with her old friend and leader, the legendary Jedi Master Revan. Revan, meanwhile, had been captured by the Emperor and detained in a form of stasis for the intervening centuries. With the conflict between Republic and Empire again heating up, Surik knew that the time had come for Revan to be freed from captivity.

Following an intelligence-gathering assault on the Imperial fortress at Taral V, Oteg led his fleet into The Maelstrom to attack the Imperial prison facility inside. A fierce battle—one of the first of the soon-to-be new war—ensued, with both sides taking heavy casualties. Ultimately Oteg's fleet prevailed, successfully retrieving Revan before withdrawing from the area. With his freedom, Oteg believed that the Republic had obtained the means by which to finally defeat the Empire.

Revan's respite and sojourn to Republic space would be brief. Now fully aware of the crisis facing the galaxy, he set out to utterly destroy the Empire with the aid of ancient Rakata technology, an automated mass-manufacturing space station known as the Foundry. The Foundry was set to manufacture countless extermination droids designed with bioscanners to detect Sith genetic material, and destroy any life containing it—which would result in the genocide of the vast majority of the Imperial population.

The Empire had prepared for this situation. Darth Malgus, long opposed to the peace with the Republic, revealed to his chosen strike team that the rescue of Revan had been Malgus' own design. He intended that Revan would lead the Empire to the Foundry, in order that it could be used by the Empire in the coming war against the Republic. The Imperial strike team was successful in their attack on the Foundry, destroying the few active extermination droids already built before defeating the Jedi "hero" himself. But rather than die, Revan vanished in a mysterious burst of light and energy, his fate unknown. After mopping up the remaining Republic starships, the Empire claimed victory—and with it, ownership of the Foundry.

Elsewhere in the galaxy, Jedi Master Tol Braga set in motion an ambitious plan which he hoped could pre-emptively avert the coming war: to capture and subsequently redeem of the Sith Emperor to the light side of the Force.

Braga's quest enlisted the aid of a rising Jedi star who, by that point, had become known as the Hero of Tython due to their role in saving Tython from destruction at the battle of the Oppressor. The Hero traveled the galaxy for this mission, seeking out clues as to the whereabouts and technical specifications of the Emperor's highly secretive space station, conducting investigations on Balmorra, Quesh, and finally Hoth. The attack on the Emperor's person went poorly for the Jedi strike team—the entire force was captured, and most of the Jedi were effortlessly subdued by the Emperor's admirable command of the dark side of the Force.