Star Wars just retconned the Sith "Rule of Two." The franchise the "Rule of Two" as a defining tenet of the Jedi's dark side counterparts long ago. Master Yoda alludes to the Ruel of Two when he learns about Qui-Gon Jinn and Obi-Wan Kenobi's encounter with Darth Maul in Star Wars: The Phantom Menace. Yoda notes that the Sith always come in pairs, with one being the mast and the other serving as their apprentice. Some More recent installments in the Star Wars canon have made this rule a bit less clear. One example comes from Star Wars: The Rise of Skywalker (now on Disney+). If there are only ever two Sith, then who are the Sith cultists who had been tending to the deposed Emperor Palpatine on the hidden Sith planet of Exegol after his defeat in Star Wars: Return of the Jedi? And where did that army of Sith troopers that were part of Palpatine's Final Order come from? A new novel, the Star Wars: The Rise of Skywalker junior novelization, retcons the meaning of the Rule of Two in a way that makes these new additions make a little more sense.
In the Rise of Skywalker junior novelization, written by Michael Kogge, Rey reads an ancient text about the Sith. The text reveals that the Jedi did not grasp the full extent of the Rule of Two. The text reads, "The Prime is one, but the Jedi are many. The Sith were Many but often emerge Ruled by Two. The Seeds of the Jedi have been Sown throughout the Galaxy, on Ossus, Jedha, Xenxiar, and Others. The Sith have no Seeds, since what they Bury does not Grow. They are the Despoilers of Worlds, and have Laid to Waste once Fertile Habitats such as Korriban, Ziost, Ixigul, Asog, and Others."
Based on this retcon, there have always been more than two Sith. The master and the apprentice that the Jedi believe are the Sith in their entirety are but the tip of the iceberg that the Sith allow the Jedi to see. They are the leaders, while the others serve entirely in shadow. It also adds new meaning to the title "Sith Lord," as these two leaders now rule over the other Sith.
This explains Exegol and the Final Order, but also some other things about the Sith that haven't ever fit well with the idea of the Rule of Two. After the execution of Order 66, the Empire used Inquisitors to hunt down the remaining Jedi. The Inquisitors were Force-users, and at least some of them former Jedi. It was unclear how they fit into the Sith power structure, but now it seems more clear. It also explains why Count Dooku, Palpatine's apprentice, had an apprentice of his own, Ventress.
What do you think of this retcon to the rule of two? Let us know in the comments.