WARNING: The following article contains major spoilers for Solo: A Star Wars Story, in theaters now.
One of the biggest talking points surrounding Solo: A Star Wars Story is the appearance of old Star Wars villain Darth Maul. First introduced in Star Wars: Episode I - The Phantom Menace, Maul (played in Solo by Ray Park and voiced by Peter Serafinowicz) was Palpatine's first Sith apprentice, whom the future emperor sent to capture Queen Amidala (Natalie Portman).
For a long time, fans believed that Maul met his gruesome end when he was sliced in two by Obi-Wan Kenobi (Ewan McGregor) at the end of that film. However, he returned in the expanded universe and his resurrection was kept as canon when Disney acquired the Star Wars franchise, though slightly altered.
For those who haven't been paying attention to the comic books or animated television shows, Darth Maul's cameo in Solo might have come as a shock, which might have been the point. However, his return to the big screen does more than just surprise long time film fans, it also raises several questions about the direction of Star Wars proper, especially when you consider the fact that the last Star Wars Anthology film also included a cameo of a famous Sith Lord -- Darth Vader. Is it just a coincidence, or is this an indication that fans and filmmakers desire the return of the Sith to the Star Wars franchise?
Luke Skywalker vehemently believed that there was good in his father. He learned the ways of the Jedi, learned to use the Force and wield a lightsaber only to discard those skills in Return of the Jedi in favor of the compassion he had in him all along, which ultimately drew his father, Darth Vader, back from the seemingly inescapable grip of the dark side. Since Vader's last redemptive act was to hurl the Emperor down the Death Star reactor shaft, Luke had effectively brought balance to the Force and caused the collapse of the Sith since there was and could only ever be a master and an apprentice, according to the ancient Rule of Two.
Though the films never explicitly explain the Rule of Two, the expanded universe revealed that it was established by Darth Bane as a way to ensure the survival of the Sith. By limiting the order to one master and one apprentice, the Sith could function beneath the notice of the Jedi Order and the Republic. It's part of the reason why Darth Sidious was able to rise to the height of power so effortlessly, and it's the reason why Luke's actions ensured that there were no more Sith in the galaxy.
The end of Return of the Jedi was pretty conclusive, which means any film that followed, no matter how skilled its writers or how beloved its characters, was going to have trouble building a worthwhile story, especially since it now had the near-impossible task of introducing a villain as impactful and as cinematically striking as the Sith.
Enter the Knights of Ren and the First Order.