Obi-Wan is forced to turn a light on when he is confronted with Vader, and not only because he's frozen with fear in the specter of death. This is the monstrous form of his failure and his hubris. This is the brother he once loved, and the “chosen one” hope of the Jedi.
The reasoning comes from, not only his fears that he isn't strong enough to defeat Vader after 10 years in hiding but the fact that facing Vader means Obi-Wan will have to face up to his greatest failure.
Losing Luke And Leia
Obi-Wan's biggest fear has to be the task he upheld for two decades, which was the protection of Luke and Leia. He spent his final years on Tatooine with the intention of watching over Luke, while the Obi-Wan Kenobi series detailed his efforts in rescuing Leia.
Darth Vader #26 finally addressed Anakin Skywalker's animosity towards sand -- by turning it into the embodiment of the Sith Lord's greatest fear.
Darth Vader was the stronger of the two by far. However, as with most lightsaber duels, the victor is the one with the greater connection to the Force. In their final fight of the series, set about nine years before the events of A New Hope, Obi-Wan hurled a barrage of rocks at Vader.
In Star Wars Legends and Canon, Galen Marek (Starkiller) is the only Jedi (other than Obi-Wan Kenobi) to put a beat down on Darth Vader/Anakin Skywalker.
Visions of Obi-Wan. The comic opens during the last moments of Revenge of the Sith, recreating the well-memed instance when a despondent, freshly-armored Vader cries out with a drawling “nooooooo” over how much he's lost.
Palpatine admits to Darth Vader that the Jedi he actually feared most was none other than Jocasta Nu. "Who?" I hear a lot of you of ask. Well, I'm sure most will recall hearing the name at some point. Now that you remember her, let's actually explain who she was.
At that moment, the one in which Vader screamed, "No!" in Revenge of the Sith, the Sith apprentice believed himself to be his own worst enemy. Vader hated himself. It likely only grew worse when Vader realized that Palpatine had absolutely played him.
#1 – Yoda. Yoda is widely considered to be the greatest Jedi of all time, and with good reason. He is a master of the Force, a skilled warrior, and has an unmatched wisdom that comes from centuries of experience. He is the embodiment of what it means to be a Jedi, and his legacy lives on long after his death.
DARK SIDE FRIDAY - Did you know Palpatine feared Qui-Gon Jinn? Palpatine was immensely powerful and he could see the future which made him very confident about pretty much anyone who stood against him. So why Qui-Gon Jinn?
Obi Wan is one of the most powerful Jedi to have ever lived. He is the best defensive duelist in galactic history according to Mace Windu and numerous factbooks. He had a low sensitivity to the force but mastered it to his fullest potential worshiping the force as opposed to bending it to his will.
Anakin admits to Obi-Wan that he has been arrogant and unappreciative of his training, and apologizes to his master. Obi-Wan assures Anakin that he is proud of him, telling him that he has become a "far greater Jedi than I could ever hope to be."
He does. Right at the end. With Luke crying over him and Vader sensing his anguish and pain he had inflicted on all those who had cared for him.
The added risk Darth Vader takes in allowing children to live in a situation where he could have killed them proves that he regrets killing Younglings and will avoid harming any more children for the rest of his days, though intense intimidation is a dark strategy to avoid repeating his Youngling massacre.
Vader, the only power who overrules him is papa Palpatine. The reason why Vader obeyed tarkin was out of a sense of respect for him as a military leader, not as his superior.
In the original trilogy, Palpatine is depicted as the Emperor of the Galactic Empire and the master of Darth Vader (Anakin Skywalker).
Yet he kept it to himself, as he didn't care about the Sith or the Force. Although Tarkin didn't believe in the Force, he respected Vader a lot, as he was the Emperor's enforcer, and he even grew to admire Vader's way of inducing fear within others.
In the Star Wars Universe, it's hard to deny Darth Vader's greatest enemy was the Jedi Order. Sure, he had enemies such as Qi'ra, the Crimson Dawn and Doctor Aphra. But few came close to truly defeating him, other than Obi-Wan Kenobi and in time, his son, Luke Skywalker.
Anakin trusted Darth Sidious, not out of sincere trust, but because Palpatine drove a wedge between him and the Jedi Council. Revenge of the Sith ended with Anakin losing most of his limbs and having to be reconstructed into a cyborg.
Vader responded “I am not your failure, Obi-Wan. You didn't kill Anakin Skywalker. I did.” This allows Obi-Wan to finally accept that Anakin is truly gone and that there was nothing he could have realistically done to save him.