A core tenet of the Rule of Two is a Sith Master passing their power and knowledge onto their apprentice once the latter kills them. It ensures that there’s always a capable master present with an emerging student beneath them, ready to take their place and carry on Sith rule. However, Emperor Palpatine, aka Darth Sidious (Ian McDiarmid), doesn’t seem to hold much stock in the Rule of Two as it’s written. In both “Star Wars” canon and “Star Wars” Legends, it’s evident that he seeks power for himself and himself alone, going as far as evading death.
In canon, Sidious takes on several apprentices, but he isn’t eager to let his power pass to them. With his final learner, Darth Vader (Hayden Christensen, who made a hilarious reveal regarding the Sith’s underwear) at his side, Sidious takes a vested interest in cloning. As seen in “Star Wars: Episode IX – The Rise of Skywalker,” he uses the technology to stay alive, transferring his consciousness to a clone body to regain his lost power following his apparent death decades earlier. He does something similar in the Legends story “Star Wars: Dark Empire,” returning from the grave in a clone body in hopes of ruling the galaxy again. In Legends, this is known as the Rule of One — or Palpatine’s Doctrine.
Seeing as Darth Sidious is defeated by Rey Skywalker (Daisy Ridley) on Exegol, decades after being defeated by Vader and his son, Luke Skywalker (Mark Hamill), it’s plain to see that the Rule of One is just as ineffective — if not more so — than the Rule of Two.
