Darth Vader didn't learn he had a daughter until Return of the Jedi, when he stood before Emperor Palpatine. The Emperor's power probed Luke's mind, attempting to goad him to fall to the dark side, and he discovered Leia's existence. "Sister," the Emperor taunted.
Vader discovers Leia is his daughter because of Luke.
It's not until Return of the Jedi, when Luke confronts Vader and the Emperor in the third act of the film, that the Sith Lord realizes his son is there to protect his twin sister.
Alderaan's princess knew she had been adopted by Bail and Breha Organa after the Clone Wars, but she had no idea who her parents were. That was until Luke Skywalker told her the truth - that he was the son of Darth Vader, and that she was his sister.
In canon, Vader found out because Luke told Boba Fett that he was “Luke Skywalker.” This was explained in the canon comic Star Wars (2015) 5. Vader only sensed Leia was Luke's sister because Luke was thinking about her on the Death Star II. When Vader tortu…
Summary. Darth Vader learns Luke Skywalker is his son shortly after A New Hope in canon and Legends comics. In canon, the reveal occurs in Marvel's Star Wars #6, where Vader vows to make Luke join him. In Legends, Vader's discovery is shown in Marvel's Star Wars #35, later expanded in Star Wars: Vader's Quest.
Yoda. Yoda's knowledge of Luke Skywalker's true parentage was also confirmed in Return of the Jedi. As with Obi-Wan, Yoda believed that Anakin's fall to the dark side made him unsalvageable, with the Darth Vader persona being his only identity following his ascension to Sith Lordship.
Leia's Force abilities and her lack of awareness of her true identity also contributed to Vader's inability to sense their familial connection. Vader's denial of Anakin Skywalker's legacy and his fear of getting hurt again prevented him from realizing the truth about his children until later in the original trilogy.
Anakin Skywalker never knew Padmé was pregnant with twins, and he believed his child had died with his wife. He had no idea Padmé had given birth before she died, still less that the Jedi had spirited the children away and hidden them.
In Star Wars Legends Leia was visited by the force ghost of her father Anakin Skywalker, the man who used to be Darth Vader. It wasn't a pleasant meeting as Leia was unable to forgive him for the things he'd done no matter how hard he begged, and it was the only time she saw him.
Anakin Skywalker was 22 years old in Revenge of the Sith, a crucial moment when he falls to the dark side and becomes Darth Vader. Darth Vader was 44 years old when he confronted Luke on Bespin in The Empire Strikes Back, attempting to seduce his son to the dark side.
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.
He eventually became so desperate to find a way to prevent Padmé from dying that his fear was ultimately the main reason that led to his fall to the dark side. Vader screaming for the loss of Padmé. Even as a Sith Lord, Anakin still loved Padmé very much, but felt great guilt for his actions against her.
Qui-Gon Jinn believed that the Force itself created Anakin in Shmi's womb, making him the Chosen One who would bring balance to the Force. The revelation confirms that Emperor Palpatine personally manipulated the Dark Side of the Force to create Anakin, making him Anakin's true 'father'.
In order to keep the children safe from Vader, who was unaware of their births, it was decided that Luke would be taken to live with his uncle and aunt, Owen and Beru Lars, on Tatooine; meanwhile Leia was taken to Alderaan as the adopted child of Amidala's friend and colleague, Senator Bail Organa, and his wife, Queen ...
As for why Anakin didn't return to free his mother, it's because he never got the opportunity. Relationships were strictly forbidden in the Jedi Order, and all of them had to forgo their own parents.
No. Neither Luke nor Leia found out they were siblings until the third film, Return of the Jedi. Indeed, it wasn't decided that they were siblings until the making of that film (because Lucas no longer wanted to make further sequels about a search for Luke's sister, and decided to wrap everything up with Jedi).
Bail Organa and Obi-Wan fabricated Padme's death and the twins' story to keep Luke and Leia hidden after the events of Revenge of the Sith. By maintaining the secret, the twins remained safe, eventually allowing them to orchestrate the Emperor's downfall and the Rebellion's victory.
Summary. Obi-Wan's seeming inability to remember R2-D2 in "A New Hope" was a deliberate choice to downplay the droid's arrival and avoid revealing too much too soon.
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.
At first, Ahsoka has no idea that Anakin Skywalker and Darth Vader are one and the same. She discovers the truth in Star Wars Rebels when she encounters the Sith Lord in a space battle. What she senses is so shocking to her that she passes out.
