- "Always two there are; no more, no less. A master and an apprentice."
The Rule of Two was a Sith philosophy mandating that only two Sith could exist at any given time: a Dark Lord of the Sith to embody power, and an apprentice to crave it. The philosophy was created by Darth Bane, the sole survivor of a war against the Jedi Order a millennium before the Clone Wars. Recognizing that it was Sith greed and in-fighting that led to their destruction, Bane created the rule so the Sith could operate in secret, using subterfuge to plot their revenge against the Jedi.
The Sith carried out their vendetta for a thousand years, gaining power in secret while the Jedi had believed that the Sith were destroyed. The Sith finally revealed themselves during the Trade Federation's invasion of Naboo, after which they orchestrated the Clone Wars so Supreme Chancellor Sheev Palpatine—secretly the Dark Lord, Darth Sidious—could destroy the Jedi and transform the Galactic Republic into the Galactic Empire. The Sith ruled the galaxy for 23 years until they were destroyed by a redeemed Anakin Skywalker—who had been Darth Vader—who sacrificed himself to kill Palpatine during the Battle of Endor.
- Star Wars: Episode I The Phantom Menace (First mentioned; albeit indirectly)
- Star Wars Journeys: The Phantom Menace (Indirect mention only)
- Star Wars: The Clone Wars – "Revival" (Mentioned only)
- Star Wars: The Clone Wars – "Eminence" (Mentioned only)
- Star Wars: The Clone Wars – "The Lawless" (Mentioned only)
- Star Wars: The Clone Wars – "Sacrifice" (First identified as Rule of Two)