Ownership of the droids R2-D2 and C-3PO changes throughout the Star Wars prequel trilogy. R2-D2: R2-D2 is initially owned by the Naboo Royal Starship, serving as the astromech droid for Queen Amidala's starship. C-3PO: C-3PO is created by Anakin Skywalker on Tatooine using spare parts.
In The Phantom Menace, set 32 years before A New Hope, R2-D2 is portrayed as belonging to the Naboo defense forces, one of three astromech droids deployed for repair duty onboard Queen Padmé Amidala's (Natalie Portman) starship as it attempts to get past the Trade Federation blockade.
Neither droid is apt to correct him, especially after his kindness becomes apparent. And in Artoo's case, he's likely all-too aware of Luke's heritage: allowing him to happily serve the young man just as he had Leia before him and Anakin before her.
After C-3PO and R2-D2 landed on Tatooine, Jawas picked up the two droids, fitting them with restraining bolts. The Jawas sold the robots to Owen and Beru Lars and their nephew Luke Skywalker, a seemingly minor event that would change the fate of trillions in the galaxy.
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 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.
Because as far as he knows it's just a generic protocol droid. There are millions of them all over the galaxy. He has no reason to think this droid is the same one he was briefly acquainted with many years ago.
R2 was later able to restore his companion during the Battle of Geonosis. After the battle, R2-D2 and C-3PO were the sole witnesses to the marriage of Anakin Skywalker and Padmé Amidala in Lake Country. After this Padmé gave ownership of R2 to Anakin while she kept 3PO.
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.
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, ...
Uncle Owen accuses them of such, and C-3PO sees an opportunity and champions for his old friend, calling Artoo, "a real bargain." Uncle Owen and Luke are persuaded enough to take R2-D2 instead. Luke meeting R2-D2 is a pivotal moment in the Star Wars universe.
Abrams also named the character, saying, "I named him BB-8 because it was almost onomatopoeia. It was sort of how he looked to me, with the 8, obviously, and then the two B's." The name was conceived early on in the film's production and was one of the few to remain unchanged.
Since Bail Organa had C-3PO's memory wiped previously in order to prevent him from spilling the secret of Leia's parentage, it could be that this was a semi-regular occurrence for the droid given he couldn't be trusted to keep quiet about things.
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.
Though it sounds like he thinks Anakin is dead, he could also be viewing it as Obi-Wan does, where he believes Anakin died when Darth Vader was created. There's a hint that Owen knows Anakin was Darth Vader by the time of A New Hope.
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.
Because he never owned a droid. R2-D2 was owned by Padme and later Anakin, and after that Bail Organa. R4-P17 was assigned to him to assist, not given to him to own. So he really never owned one.
However, the same could not be said for R2-D2, who never had his memories erased. While there isn't a canonical reason for this decision, the likely explanation may have been that Threepio was more likely to say something he shouldn't have.
After decades of missions with R2-D2, Luke Skywalker was reasonably fluent in droidspeak. The most common way for binary droids to communicate with organics was by writing, conveyed via another computer system. This is how astromech droid copilots would speak with the pilot of a starfighter.
