C-3PO accidentally became part of the Battle of Geonosis when his head was affixed on top of a battle droid's body after a mishap in the Geonosian droid factory. R2-D2 and C-3PO witnessed the secret wedding between Anakin Skywalker and Padmé Amidala on Naboo.
C-3PO was a recreation of Anakin Skywalker after he was found in the dunes of Tatooine by Anakin and a fellow slave friend. He later became in possession of Anakin's wife, Padmé and then their children, Luke and Leia. C-3PO and R2 were the only ones who knew Anakin and Padmé were married.
They may not know the extent of Anakin's relationship with Padmé, or even that they are legally married, but it seems abundantly clear that Yoda, at the very least, was aware of Anakin's strong attachment to Padmé, and that those feelings were reciprocated, too.
The sequence calls back to a similar scene in Revenge of the Sith, when Bail Organa orders Threepio's memory be erased to prevent him from sharing information about Anakin Skywalker's fall to the dark side.
Although C-3PO is a tell-all, it's possible that he was directly programmed not to say who Leia is. This is something that George Lucas himself suggested in an interview back in the 1970s, which made it into the book The Making of Star Wars: The Definitive Story Behind the Original Film.
C-3PO Remembers Anakin Skywalker & The Past (Flashbacks) Star Wars
Did C-3PO know Anakin was Darth Vader?
The question being answered is: “Do R2D2 and C3PO know that Darth Vader is Anakin?” C-3PO? Definitely not. As many other have pointed out, C-3PO had his memory wiped at the end of Episode III, so it is almost certain that he does not know.
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.
Darth Vader's true identity as Anakin Skywalker was a highly guarded secret, known only to a select few individuals including Palpatine, Obi-Wan Kenobi, Luke, Han, Leia, R2-D2, C-3PO, Master Yoda, Bail Organa, Ahsoka Tano, Darth Maul, Grand Moff Tarkin, Grand Admiral Thrawn, Jocasta Nu, Ferren Barr, Verla, Reva, ...
At the end of Star Wars: Episode III - Revenge of the Sith, C-3PO's memory was wiped, allowing him a fresh start by the time A New Hope begins, but R2-D2's memories remained intact, which is why many fans wonder why he didn't tell Luke the truth about his family history, but he might have not done that because he didn' ...
When Anakin fell to the dark side and became Darth Vader, Yoda was saddened, but firmly believed he was beyond redemption and forgiveness, and ordered Obi-Wan to hunt down and kill him. Even as a Force spirit, Yoda continued to believe that Vader was irredeemable and there was no good left in him.
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 ...
Perhaps, Darth Vader just figures that this is another protocol droid and not C-3PO. Obviously, C-3PO does not recognize Vader because his memory was wiped at the end of Revenge of the Sith.
They aren't abbreviations — they're model and serial numbers. R2 is a second generation R-series astromech, serial number D2. * And C-3PO is a C-series protocol droid with the serial number 3PO.
However, the animated series and comics are now revealing that the Sith Lord showed what Padmé meant to him even after his transformation. Considering his position as a servant of Emperor Palpatine, it can be assumed that Vader eventually moved past his feelings.
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.
Maybe R2-D2 didn't know Darth Vader was Luke's father because he didn't see Palpatine christening him Vader, or maybe he believed Anakin was dead because even Obi-Wan didn't know Anakin was alive.
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.
What's going on: Anthony Daniels, who plays the C-3PO role in all of the nine Skywalker saga films, recently told HuffPost that he wasn't sure why Obi-Wan Kenobi didn't know C-3PO. He said it's possible Obi-Wan knew too many droids.
