Star Wars There's a relatively even split between the Sith who started out as Jedi and the Sith who didn't, at least in terms of Star Wars movies and TV shows, but those who started out as Jedi have a clear advantage that makes them even more dangerous. Some of the Star Wars the most powerful Sith were first trained in the Jedi Order. While Anakin Skywalker/Darth Vader is probably the most prominent name that comes to mind, he was far from the only one – or the first – to turn away from the Jedi and embrace the dark side.
This is not the path of every Sith Lord. There are also several Sith in Star Wars who has only known the dark side of the Force. Being trained in the dark side early on and falling to the dark side after being trained by the Jedi have their advantages in terms of overall power, but Sith who were first trained as Jedi have a higher threat level based on their unique experience and training.
Darth Plagueis, Darth Sidious and Darth Maul were never Jedi
Among the Sith who didn't start out as Jedi are some of the most fearsome names in the galaxy. In truth, the Sith lineage of Darth Plagueis, Darth Sidious, and Darth Maul exclusively comprises Sith who have been trained only in the dark side of the Force. Of these three, the least is known about Darth Plagueis in terms of his canon. Star Wars history.
Plagueis had an extensive history in Star Wars before the restructuring of the franchise following the acquisition of Disney, which saw almost its entire history relegated to Legends. Star Wars maintained that Plagueis was canonically the Sith master of Palpatine/Sidious, and Plagueis finally made his first on-screen appearance in The Acolyte. While little is known about the character thus far, it's clear that he was incredibly powerful. Even his brief participation The Acolyte the ending was bone-chilling, and in Star Wars: Episode III - Revenge of the SithPalpatine confirmed that Plagueis could create life and prevent death.
Palpatine confirmed that Plagueis could create life and prevent death.
Even with its more limited history in Star Wars canon, it is evident that Plagueis wielded immense power and (however mockingly Palpatine may have intended the description, since he killed his master) was truly wise. It appears he also passed much of this power and knowledge onto his apprentice, Sidious. Darth Sidious is easily one of the most powerful and dangerous Sith in Star Wars. While Palpatine/Sidious certainly had plenty of raw power, he rarely needed to exert himself Star Wars films and programs; his true strength was in manipulation.
Palpatine effectively manipulated his way to the top of the Galactic Republic, which allowed him to transform the Republic into a Galactic Empire entirely under his control. This was quite different from his first Sith apprentice in the prequel trilogy, Darth Maul, who had raw, indomitable rage but very little discipline. Perhaps it is for this reason that Maul was cast aside so quickly, even after Palpatine discovered that he did not actually die in Star Wars: Episode I - The Phantom Menace.
Darth Vader, Count Dooku and Qimir were all raised in the Jedi Temple
As mentioned, probably the most well-known fallen Jedi who became Sith is Anakin Skywalker/Darth Vader. Anakin was not just one of Star Wars the most powerful Jedi, but also the Chosen One, prophesied that he would bring balance to the Force (and, based on the Jedi's interpretation, destroy the Sith). It goes without saying that Anakin was one of the most powerful characters in Star Warsboth when he was on the dark side and when he was on the light side.
Like Anakin, Palpatine's second Sith apprentice in the prequel trilogy, Count Dooku/Darth Tyranus started out as a Jedi. In fact, Dooku went much further than Anakin in the Jedi Order and grew to have the respect of some of the Order's most prominent Jedi. This was evident when Mace Windu refused to believe that Dooku could be behind Padmé's assassination attempt - even though he really was. Dooku was known for being arrogant, and while he certainly was, he was also intelligent and quite skilled with a lightsaber.
The Acolyte introduced yet another Jedi-turned-Sith, Qimir, who was a completely original character to the series. Although Qimir's story was somewhat interrupted by The Acolyte cancellation, the show revealed that Qimir had previously been apprenticed to Jedi Master Vernestra Rwoh. It was also quite clear that Qimir was extremely powerful, given how easily he took down several Jedi in The Acolyte episode 5 alone.
The Jedi offer something the Sith never could
While Darth Vader, Count Dooku, and Qimir are excellent examples of how powerful Sith who have been trained as Jedi can be, Plagueis, Palpatine, and Maul reveal that some of the most dangerous Sith in the galaxy were never Jedi. However, Sith who started out as Jedi have the benefits of Jedi training on their sidemaking them an even greater threat. This can even be seen in the deaths of Plagueis, Palpatine, and Maul, who fell due to hubris.
Jedi teach young people and Padawans to control their emotions, exhibit self-control, and approach issues impartially.
Jedi teach young people and Padawans to control their emotions, exhibit self-control, and approach issues impartially. The Sith, on the other hand, are almost entirely reactive and driven by anger and hatred. While giving in to anger can lead to raw power, the discipline learned from the Jedi can give the Sith the ability to hone their anger and be even more strategic.
Arguably, if Anakin had not been so severely injured in his battle with Obi-Wan on Mustafar in Revenge of the Sithhe may well have become the perfect example of this. Anakin/Vader had the potential to become the most powerful being in the galaxy, and it would have been a combination of his inherent power in the Force, his training as a Jedi, and his freedom to now use his anger and hatred that would have triggered this. While Sith Lords everywhere Star Wars demonstrated their power, those who were also fallen Jedi posed a particular threat.