So, Vader let him go so that Obi-Wan could regain his full strength because what Vader really wanted was to prove that he was more powerful than his master ever was -- and offing "Ben Kenobi" would have been a massive letdown.
However, as shown in Marvel's Star Wars: Darth Vader #5 (by Greg Pak, Raffaele Ienco, Neeraj Menon and Joe Caramanga) it wasn't envy of power that drove Anakin over the edge, but rather something far more personal: Skywalker believed that Padme and Obi-Wan might have had an affair.
The duel ended with Obi-Wan's death and the disappearance of his body (we would later find that he had turned into a Force ghost), and Luke had to come to terms that his mentor is gone.
Through careful wordplay and Obi-Wan's casual relationship with the truth, his statement of never owning a droid in "A New Hope" serves as a cover to hide his past companionship with R2-D2.
Darth Vader acts like he doesn't even know C-3PO or R2D2. They were with him since he was a child. He did everything he could to forget his past. Also, his plating had been replaced many times, and protocol droids all look very similar.
from Yoda, rather than feeling relief. or vindication at finally destroying his old master, Vader, or rather Anakin, was instead. overwhelmed with utter loneliness and sorrow, having killed one of his last. remaining links to his former life.
Summary. Obi-Wan spared Anakin despite knowing killing him would "burn his heart to ash" and feeling regret for what Anakin could have become. Obi-Wan's decision to spare Anakin was influenced by the dark feeling that accompanied Emperor Palpatine's arrival, preventing him from finishing him off.
However, when it comes to who Darth Vader hates more than anyone in the Star Wars galaxy, himself and Obi-Wan Kenobi don't hold a candle to the true point of Darth Vader's hatred, Emperor Palpatine. Star Wars: Darth Vader #39 by Marvel Comics is available now. Please verify your email address.
This fell in line with various fan theories and non-canon novelizations that suggested Obi-Wan and Padmé had an affair sometime during the Clone Wars. In the Star Wars prequel movies, Obi-Wan often has a duty to protect Padmé, but there was never any sense of romantic feelings.
Darth Vader did not 'forget' he was Anakin. He believed he was not Anakin Skywalker; a completely different person whom he killed. You will read in EU materials, that he referred to his memories as Anakin, as 'The Jedi'. He suppressed most of Anakin Skywalker's memories - his memories while he was Anakin.
And despite Vader's weaknesses, it's not as if Luke was unskilled, as he spent plenty of time honing his connection to the Force after Star Wars: The Empire Strikes Back, and was likely the most skilled lightsaber-wielder Vader had faced in a long time.
After defeating Darth Vader in the Obi-Wan Kenobi finale, Obi-Wan broke down and began tearing up when he saw Anakin's scars. It was the first time he had seen Anakin's face since leaving him to burn on Mustafar, and so he apologized for everything that had happened.
The canonical comic Star Wars: Darth Vader #7 confirms the younglings' deaths caused Anakin grief, self-loathing, hatred, and pain, fueling his descent even further into the Dark Side.
A year later, in 4 ABY, with his health rapidly declining, Yoda died of old age when Skywalker returned to see him. He became one with the Force, shortly before Luke redeemed his father Anakin, who fulfilled his destiny as the Chosen One by killing Sidious.
Instead, the theory suggests that Padmé died because Palpatine killed her. By taking a closer look at how Anakin's transformation into Darth Vader is intercut with Padmé's death, a clearer picture emerges of how Padmé's death was more likely a planned-out murder as opposed to an accidental tragedy.
During the battle, Anakin, who had been known as the Sith Lord Darth Vader, was redeemed by Luke and brought balance to the Force. However, the redemption cost Anakin his life, having been mortally wounded by the Emperor, Darth Sidious, while killing his former Master.
Vader constantly regretted what he had done - he knew he made an unbelievable mistake. But, he also knew that it was much too late to change anything. He had to live up to what he had done - and the best way to do that was through embracing his hatred and anger, letting it grow and fester in him.
Many are often shocked to find that Obi-Wan was only 57 years old when he died fighting Darth Vader in A New Hope. For many, the issue of Obi-Wan's age is a plot hole, as he was initially seen as this old solitary man, but Star Wars made him younger than he looked in the original trilogy.
R2-D2 was present when Padmé gave birth to Leia and Luke, so he knew Luke was Anakin's son – but what he didn't know was that Anakin became Darth Vader. In addition to that, Anakin's fall was surely a painful event in R2-D2's life, one that he definitely wouldn't like to remember or even talk about.
Obi-wan responds to starwars.wikia.com/wiki/Luke_Skywalker saying R2 belongs to him with, “I don't seem to remember ever owning a droid,” which is technically true, because Obi-Wan never did “own” R2 or C-3PO. Obi-Wan then makes a comment that suggests he's more than aware of R2's impressive capabilities.
