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.
Master Yoda knew that Darth Vader was once Anakin Skywalker - the boy he sensed too much fear in to train way back in Star Wars: Episode I - The Phantom Menace. For many years it's been assumed Master Yoda was aware from the day Vader gained his cybernetic enhancements and signature wheeze.
Returning to Dagobah to complete his training, Luke learns from an ailing Yoda the terrible truth that Vader is his father. The Jedi Master also offers Luke a tantalizing secret -- that there is another Skywalker.
When Star Wars' original trilogy was released, there were only a relative few characters who knew Luke was Vader's son: Bail Organa, the Lars family, Obi-Wan, Yoda, and Palpatine. By the end of A New Hope, all but Yoda and Palpatine were dead.
Instead of being in the life suit, Vader looks like an older Anakin who never received the devastating injuries, and Padmé and Luke (who struck down Palpatine) are by his side. It's during these visions Palpatine realizes Luke - who he only knew as the Rebel who destroyed the Death Star - is Anakin's son.
How RED LEADER Knew Luke was Anakin Skywalker's Son - Explain Star Wars
How does Darth Vader realize Luke is his son?
Vader was hunting down the pilot who blew up the Death Star, and hired Boba Fett to find them. Boba was unable to, but he did give Vader a name: “Skywalker.” This, combined with his knowing Luke was Force-sensitive and had been trained by Obi-Wan, was what made him realize the truth.
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.
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.
Why did Obi-Wan say Darth Vader killed Luke's father?
The scene explains Obi-Wan's explanation to Luke that Darth Vader murdered Anakin Skywalker, because in a way, he did. The dark side of the Force is all-consuming. Once someone starts down the path to the dark side, it can be difficult to return to the light.
Does KYLO Ren know Darth Vader is his grandfather?
Kylo Ren was always obsessed with his grandfather. He didn't learn he was the grandson of Darth Vader until he was a teenager, when a recording from Bail Organa - intended to be a private message for Leia - was shared with the entire galaxy.
He was, of course, alluding to Leia, and he died immediately after finishing his statement. Like Obi-Wan, Yoda appeared as a Force ghost after his death, but these final living words were surprising to characters and fans alike.
He was still completely unaware of the Sidious/ Palpatine connection until ROTS. He also said during TCW season 6 that the Jedi order must believe in the clones and end the war before the Sith's plans are realized.
To answer the original question, I'm pretty sure that R2 never knew that Anakin became Vader. He wasn't there when Anakin was named Vader, he didn't know what happened on Mustafar. All he knew is that Anakin told R2 to stay with the ship, and that was the last time R2 saw Anakin.
Despite seeing Vader as an idol, Kylo conveniently ignored his grandfather's redemption. He was well aware of what happened, and it's likely Luke himself who told Ben about the events of Star Wars: Return of the Jedi.
Qui-Gon believed Anakin was the Chosen One, prophesied to bring balance to the Force, and that their meeting was no accident. He brought Anakin to the Jedi Council on Coruscant, and was angered when his fellow Masters refused to train the boy, but saw their lack of vision as only a temporary setback.
secondly, in Legends, R2 was given programming that actually restricted him. from sharing any information with Luke or Leia. about their parents or relation to one another. this was all part of the plan. to conceal this information from the twins.
Darth Vader only learned he had a daughter in Return of the Jedi - but there's no evidence he realized she was Leia before his death and redemption. Darth Vader may have never known Princess Leia was his daughter in Star Wars and never cultivated a relationship with her, even when he was a Force ghost.
This could be interpreted as Obi-Wan showing either pity or mercy for his old friend. Despite everything they have been through, the Obi-Wan Kenobi show has firmly established that the Jedi still deeply cares for his former Padawan and remembers him as the great ally he's had for many years.
The movies themselves pick up at the end of the conflict, in Star Wars: Episode III - Revenge of the Sith. Anakin Skywalker is 22 years old at this point in the timeline, a crucial moment in his life when he falls to the dark side and becomes Darth Vader.
Luke and Leia only discovered they were twins in Return of the Jedi despite being Force-sensitive. Could they have known earlier in Star Wars? Luke and Leia never sensed that they were twins until Return of the Jedi despite both being sensitive to the Force.
You saw how Luke's attitude completely changed when he realised that was actually Yoda and so did Yoda's behaviour. As for the r2 thing, is incredibly likely he just suspected R2 had had his memory wiped several times since they last saw each other.
C-3P0 didn't; his memory was wiped at the end of Revenge of the Sith to prevent him from spilling the beans. Why was Anakin always more attached to R2D2 even though he literally built C-3PO? R2-D2 was almost constantly around Anakin Skywalker during the Clone Wars, serving as his personal astromech.
