Long ago, over a hundred years to be certain, though none knew for sure the exact date, the last practitioner of the Sith, the last Darth, died. This severely weakened the sith religion, as there was no leader. And, though the terror of the Sith Lords had long been forgotten, the word "Sith" has taken on a new meaning.
A new Sith Empire, consisting of worlds and companies controlled by self-proclaimed "Sith Arisocrats", have chosen to leave the Republic and create a new empire in the expansion region of the outer rim. Where they could make their own laws. The Republic allowed them to continue their bid for power as the Sith Aristocrats had such great financial and political power, that their elimination would harm the Republic more than it would help it. The Republic thus considered the Sith a necessary evil.
However, all that is necessary for antagonism to succeed is that protagonists do nothing… the Sith have attempted to annex worlds from the Republic. Those they could not buy, were taken by force…
The Republic grew afraid that there was no way to avoid yet another war. While the CIS(confederate of Independent Systems) has been established on Geonosis. Led by Count Dooku and General Grievous.