Rule of Two/Legends

"Always two there are: A master, and an apprentice. No more, no less."

- Master Yoda

"Always two there must be. No more, no less. One to wield power, and one to crave it."

- Darth Bane

The Rule of Two was the guiding principle of the Sith after the internecine New Sith Wars. To avoid the seemingly inevitable clash between power hungry Sith, and based on his own view that the Force was finite, Darth Bane hid from the Jedi and invoked the rule, which stated, There may only be two Sith at a time in the galaxy&mdash;a Master and an Apprentice. With this rule, Bane was able to avoid further intra-Sith conflict and continue the Sith Order.

Some similarity can be seen between the Sith Rule of Two and the Jedi custom of a Master having only one Padawan at a time. Bane may even have based his Rule on this custom, seeing how 'correct' and effectiveit have been during history.

For 1000 years they watched and waited, doing their best to destabilize the Galactic Republic without revealing themselves. At some unknown point, soon after the establishment of the rule, the Sith encountered the Jedi again, and again were thought to be destroyed. The Sith in fact survived, but they divulged both the identity of Bane, as well as the rule of two. Many centuries passed. Finally, one Sith Lord, Darth Sidious, under his true guise of Palpatine was elected Supreme Chancellor, masterminded a civil war in the Republic, and, as Emperor Palpatine, brought the galaxy under the control of the Sith.

Darth Bane, however, overlooked one possibility: That one of the Sith Lords may be redeemed. When Darth Vader murdered Palpatine, there were no others to carry on the order's traditions and teachings. Once again, the Sith had destroyed themselves.

However, after the Galactic Civil War, the New Republic and New Jedi Order were opposed by the Cult of Ragnos, which nearly ressurected the spirit of Marka Ragnos on Korriban in the Valley of the Dark Lords. This institution broke the Rule of Two, as it was broken by the Prophets of the Dark Side and all Imperial Remnants and Sith Remnants.