Because his body had been severely burned on Mustafar, Darth Vader was thought to have lost much of his Force potential, although he nonetheless retained an incredibly high midi-chlorian count.
In a Vanity Fair interview from 2005, George Lucas went deeper into why Anakin became much weaker as Vader. In the interview, he explained that because Anakin's limbs were severed and replaced by robotics, it was harder for him to use the Force than it was before his battle with Obi-Wan.
Once the heroic Jedi Knight named Anakin Skywalker, Darth Vader was seduced by the dark side of the Force. Forever scarred by his defeat on Mustafar, Vader was transformed into a cybernetically-enhanced Sith Lord.
In Star Wars: Revenge of the Sith, Anakin probably lost his duel to Obi-Wan on Mustafar because he wasn't using a key part of his power. Anakin's lava-filled duel with Obi-Wan Kenobi on Mustafar is one of the best and most consequential duels in all of Star Wars.
“The tear [on Anakin's face] says that he knows what he's done, but he has now committed himself to a path that he may not agree with… but he is going to go on anyway. It's the one moment that says he's self-aware that he's rationalizing all his behavior.
As Darth Vader, Skywalker was believed to have had roughly eight-tenths of the strength of the Emperor. Nevertheless, Vader wielded tremendous power and skill, enough to use the Force to overpower almost any opponent he could not defeat with his lightsaber.
Darth Sidious was always stronger than Vader, which is why he ruled over him for almost 20 years and turned him into the Sith Lord he was.
Darth Vader defeats Darth Maul. The two Sith Lords engaged in a lightsaber duel, going through the volcano and onto a bridge situated over a river of lava, which collapsed, though they both survived and continued their battle.
Obi-Wan knew it was only a matter of time. So, he made the difficult decision to use his learnings and become one with the force, rather than let Vader decapitate him.
One of the main reasons why Yoda would've won against Anakin is simply because he was far better trained than him. Yoda could see the moves his opponents were going to make before they made them; therefore, battling against Anakin would've put him at a far heavier advantage.
Although the decision to turn to the Dark Side was Anakin's alone, the choice did not come from thin air. His natural prone to impulsivity and emotion without the support systems he needed in place made it easier for Anakin to stumble down a path of darkness.
palpatine realized that perhaps he held a. sliver of affection for Vader, something that he never felt for Maul or Dooku. he knew that he would never find another being. even half as powerful as Vader, and to replace him at that point, he would need to learn to conceive life.
Lack of emotional intelligence – As you might have gathered, Lord Vader has a temper problem, and his employees bear the brunt of his frustrations. The man loves to Force-choke folks who don't fall in line, usually right in front of their peers.
1 Darth Sidious
There has been no Sith, as powerful, meticulous, nor as evil as the Emperor himself, Darth Sidious. As previously mentioned, Sidious trained in the Dark Side by Darth Plagueis before Sidious killed Plagueis in his sleep, making Sidious a Sith Master.
Most specifically though, Vader hated the most important person in his life, his son Luke Skywalker. Vader believed that Luke was the only thing standing between him and ultimate power. So, in short, the person Darth Vader hated the most was his own son- Luke Skywalker.
Darth Vader's mentor, Darth Sidious, was one of the most powerful Sith to ever live. The few times he did fight, he was seemingly unstoppable. While the version of Sidious seen in Star Wars: Return of the Jedi was easily beaten by Vader, he wasn't necessarily at full power due to his old age.
Top-tier Jedi and some Jedi with specific advantages against Vader (OT Luke, Obi-Wan) could beat him by themselves.
Introduced in the first film in the original Star Wars trilogy, Governor Tarkin is the Grand Moff of the Galactic Empire and commander of the Death Star.
Master Yoda has risen above all others to claim the top spot as the most powerful Jedi of all time and the true chosen one according to IGN's audience. He won pretty handily as well, as he was victorious in 89,756 of his 95,243 battles and had a win percentage of 94.2%.
Aside from agility and telekinesis, Yoda could absorb and redirect Force attacks, like lightning. Because of his higher understanding, he would easily overcome Darth Vader in a fight, though that doesn't mean it wouldn't be a difficult battle.
There are certainly scenarios where Darth Vader would have the upper hand in a duel with Yoda, but in most cases, Yoda would be the more likely victor. Vader wields absurd levels of Force power during his dark side prime that would certainly rival Yoda's own abilities, but likely not exceed them.
In the process, the Emperor enhanced his apprentice's abilities as he earned back his spot in the Empire. Growing in his power, Vader's confidence that he can kill his master gives him a new perspective. “You can destroy the Emperor.