Jedi who fall to the dark side are among the most dangerous Sith inStar Wars—and there’s a reason for that.Star Wars’most powerful Sithcomprise a mix of Jedi who fell to the dark side of the Force and Sith Lords who were only ever on the dark side. There’s no question that many Sith who were never Jedi are still formidable, such as Palpatine.
By nature of being raised in the Jedi Temple and learning the way of the Jedi before turning to the dark side, though, the Sith who are fallen Jedi pose quite the threat. These Sith know the light side of the Force as well as the dark side, and they are intimately familiar with the weaknesses of the Jedi, which they can then exploit. Because of that,Fallen Jedi make the most dangerous Sith—and these 5 Sith inStar Warsprove it.

5Qimir
AlthoughThe Acolyteproved to be incredibly controversial for myriad reasons,many viewers liked Qimir/the Stranger, the newest Sith inStar Warsmovies and TV shows. This plot was only minimally explored, and it was clear the intention was for this story to be a focus in a second season (that never came to be), butThe Acolyterevealed that Qimir was the former Padawan of Jedi Master Vernestra Rwoh. Evidently, that history made him extremely dangerous.
Qimir was the former Padawan of Jedi Master Vernestra Rwoh.
InThe Acolyteepisode 5, Qimir absolutely decimated an entire group of Jedi, cutting many of them down in one blow. Although certain Jedi impressively held their own, such as Padawan Jecki Lon, it was clear that Qimir had a massive upper-hand. Part of this was because these Jedi hadn’t been trained to be soldiers the way the prequel trilogy Jedi had, but it was also obvious that Qimir’s connection to the dark side and his knowledge of the Jedi made him a major threat.
4Count Dooku
Palpatine Played Dooku, But Dooku Was A Formidable Opponent
Although Count Dooku was manipulated by Palpatine, as was everyone else in the prequel trilogy era, he was also a powerful Sith. In fact,Dooku managed to hold his own in battles with Obi-Wan Kenobi, Anakin Skywalker, and Yoda, some ofStar Wars’most powerful Jedi, inStar Wars: Episode II - Attack of the Clones. This is really the perfect example of how being trained as a Jedi makes a Sith all the more powerful, given Dooku’s Jedi Master was Yoda himself.
Dooku’s Jedi Master was Yoda himself.
Yoda’s influence and training undoubtedly shaped Dooku into the Jedi—and, inadvertently, the Sith—that he became, as his control of the Force was a major factor in why he was so powerful.Star Wars: The Clone Warsalso revealed just how crafty Count Dooku was, not only because of his role as the leader of the Separatists during the Clone Wars but also because of his dealings with characters like Asajj Ventress. Arguably, had Dooku not gotten caught up in Palpatine’s master plan, he could have become an even greater Sith Lord.
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3Darth Nihilus
Darth Nihilus Is A Truly Terrifying Sith Lord
Darth Nihilus is one of the most terrifying Sith inStar Wars, not only because his mask is so horrifying (although it is), but also because he wielded immense power. Originally, Nihilus was a Jedi Knight who fought in the Mandalorian Wars. After watching the destruction of Malachor, however, Nihilus became twisted and turned to the dark side.Darth Nihilus then became one of the most dangerous Sith in all ofStar Wars.
Darth Nihilus was known as the Lord of Hunger because he had the ability to consume planets. This is a power the likes of which have never been shown on screen inStar Wars. Although little is known about Nihilus' time as a Jedi, it’s clear that he already possessed incredible strength in the Force, and he absolutely became one ofStar Wars’most terrifying and formidable Sith.
Darth Nihilus was known as the Lord of Hunger because he had the ability to consume planets.
2Darth Revan
Darth Revan Is Perhaps The Most Popular Sith In All Of Star Wars
Darth Revan is a fan-favorite Sith Lord inStar Wars, and while he hasn’t been shown on screen yet,Darth Revan has been canonized. He has become so popular in part because of his power but also because of his story. Revan began as a Jedi, but he was also an idealist who was frustrated when he felt the Jedi Order wasn’t doing enough, specifically when it came to the Mandalorian conflicts. Despite that origin, Revan was ultimately turned to the dark side by the Sith Emperor.
His story only gets all the more complicated from there, but this complexity has made Revan one of few characters who truly brought together the light and the dark side. It will be interesting to see if DisneyStar Warsexplores Revan’s story on screen in the future, but even without that, it’s undeniable that Darth Revan was one ofStar Wars’best Sith. His affiliation (off and on) with the Jedi only made him all the more dangerous.
1Darth Vader
Darth Vader Is The Most Terrifying Jedi Turned Sith
Out of all the Jedi who became Sith, Darth Vader is certainly the most powerful and the most dangerous. When he was a Jedi, Anakin Skywalker was already among the most powerful Force users of all time, which was evident enough given he wasthe Chosen One. When he turned to the dark side and became Darth Vader, his power grew that much more. In fact, had Obi-Wan not damaged Anakin/Vader so severely on Mustafar, it’s difficult to say how powerful he would have become.
Anakin/Vader’s history as a Jedi absolutely contributed to his dangerousness as a Sith. After all, that is precisely how Vader managed to get into the Jedi Order during Order 66 and wipe out so many of the Jedi. Of all the Sith who began as Jedi inStar Wars, Darth Vader was certainly the most dangerous, but each of these Sith Lords proves that it is fallen Jedi who become the most formidable Sith.