The Jedi Rebellion was the name given to the Jedi uprising against the Imperial Order of the Sith, though it later spread to the other Sith Orders in the galaxy.
Like a conflagration, the conflict quickly spread across the entire galaxy, involving nearly every governing entity in the Milky Way. In a mirror of wars in the Old Galaxy, the Jedi Rebellion began as a conflict between Force orders but quickly escalated to include the respective orders' allies. Within weeks, the entire galaxy was embroiled in the war.
Traitor in the Midst
The roots of the conflict can be traced back to the year 300 NE, when Jedi Knight Karys Scurro was granted the rank of Master and given an advisory post on the Jedi High Council, where he was to act as the resident authority on Sith matters. But unknown to anyone, Master Scurro was secretly a fully trained Sith Lord adhering to Lord Azeroth's Rules of Two, a Sith order unknown to any other Force order in the galaxy.
Upon gaining full-time access to the Jedi Council, Scurro began implementing his plan. He planted vague hints of a growing Darkness and gave testimony of disturbing and dark visions of an Imperial Sith power grab. The Grand Master, an exceptionally conservative and traditionalist Jedi, already harbored deep anti-Sith sentiments. He was only too willing to believe the worst about them.
As the years went on, Master Scurro's vague hints began to grow increasingly clear and pointed to imminent action by the Sith to seize power across the galaxy. Finally, in 307 NE, Scurro used the Dark Side to plant vivid visions into the minds of several prominent Jedi Council members. Once they related what they saw to the Grand Master, the decision was made to strike at the Sith before the Darksiders could make their move.
Siege on the Sith Temple
The Jedi Grand Master sent word to the Jedi Temple on Korribanos that the Jedi were moving against the Imperial Sith before the Sith could use the power of the Empire to seize power over the entire Milky Way. They were told to infiltrate the Sith Temple and neutralize the Sith leadership with the hopes that in doing so, they would minimize the bloodshed and end the conflict quickly. As it happened, the Master in charge of overseeing the Korribanos Jedi Temple had secretly entered into a love affair with Arika Walker, the daughter of Darth Lycan, Galactic Emperor and Sith Grand Master. Arika, who was trained as a Sith Lord, felt little loyalty to either the Sith or the Empire, agreed to grant the Jedi access to a secret entrance into the Sith Temple.
The Jedi infiltrated the Temple early one morning, but even given their perceived advantage, the Sith quickly gained the upper hand, driving out the invaders. The next day, after securing the Sith Temple against a repeated attack, Emperor Lycan waged official war on the Jedi Order, later amending that declaration of war to cover the allies of the Jedi, who had stepped up in support of the Order.
As a result of her role in the infiltration, Arika Walker was sentenced to death for acts of treason against the Empire and the Sith Order.