Explaining Knightfall Vader's Power
It seems many members of KMC remain speculative of Vader's power, perhaps it's mere hyperbole or embellishment, the words of a stunt coordinator. I'm here to prove that it's more than that:
Firstly, let's confirm that Anakin is more powerful than Yoda and Sidious as of Revenge of the Sith:
Gillard also reports that the duel will explain how Obi-Wan is able to defeat his protege, even though Anakin has been established as the most powerful Jedi who ever lived.
- The Making of Revenge of the Sith
Anakin Skywalker is the most powerful Jedi in over a thousand years.
- Star Wars Miniatures Ultimate Missions: Revenge of the Sith
Even as of Labyrinth of Evil, Anakin is as strong as anybody who'd ever sat on the Jedi Council:
Clearly Anakin was as strong in the Force as any Jedi who had ever sat on the Council. But as Obi-Wan had told him time and again, the essence of being a Jedi didn't hinge on attaining mastery of the Force, but on attaining mastery over oneself.
- Labyrinth of Evil
As of Revenge of the Sith Anakin has boundless powers:
Skywalker was seduced by the dark side of the Force. His boundless abilities fueled a sense of pride that hastened his fall.
– Star Wars Databanks: Darth Vader
After turning to the dark side, Darth Vader became much more powerful. The only character to tap into level 9, higher than Yoda:
"There’s up to eight levels. Yoda is an eight, Mace Windu is an eight, Obi is a seven, but if you miss a level, it’s a bit like taking drugs to get enlightenment.” Anakin is the perfect example of messing with the established system. “I’ve got him down as an eight or nine, which doesn’t really exist,” says Gillard, before explaining that by turning to the Dark Side, Anakin skipped some essential steps.
"It's like the richter scale, the gap between each level is enormous."
- Nick Gillard
To further grasp the massive gap between levels, Obi-Wan Kenobi only went up one level between The Phantom Menace and Revenge of the Sith:
"Obi-Wan has gone up one level from Episode I to Episode III, but it's a huge jump from one level to another."
- Nick Gillard
This tier system was personally used by George Lucas:
Gillard also revealed a rating system used by Lucas and himself to define a Jedi’s relative skill, and how it reflects the difference between light and dark.
- Den of Geeks
For those still speculative of the Canonicity of these statements. A similar level system was employed by Lucas during the production of Empire Strikes Back:
The idea of Vader using telekinetic powers during his fight with Luke was created during story meetings. There was concern, however, that the audience might think back to the first film and wonder why Vader didn't use all his powers on Ben; but this was easily explained by the fact that Ben was probably stronger than Vader. George Lucas and Leigh Brackett also discussed the different levels of the Force; maybe Ben was a six, Vader was a four, Luke is now at level two.
- The Making of Empire Strikes Back
He's further confirmed to be unparallelled, the deadliest, as a Sith Lord prior to Mustafar:
Palpatine elevated himself to the position of Emperor, and dispatched Vader as his ultimate enforcer. With his unparalleled Force abilities, Vader swept through the Jedi Temple.
– Star Wars Databanks: Darth Vader
Darth Vader will prove to be the most deadly character in the film.
- Pablo Hidalgo, Just The Facts - Episode III, theforce.net
Further confirmation that Vader's power was growing even still:
He could feel his power growing, indeed. He had the measure of his “Master” already; not long after Palpatine shared the secret of Darth Plagueis’s discovery, their relationship would undergo a sudden … transformation.
- Revenge of the Sith
Darth Vader reached a level of power that was purely his own, and beyond anybody else in the galaxy. By the time he was in his prime, he was an entirely higher magnitude of power than Master Yoda, and thus Darth Sidious, was.
It is my belief that neither DE Sheev nor FOTJ Luke managed to achieve that power given that Vader was clearly tapping deeply into his incomparable potential, so much so that neither of his competition could possibly have replicated him in their individual primes.