The Star Wars saga is plagued with plot holes, and not just the sequel trilogy. One that has bugged fans for years is why R2-D2 never told Luke Skywalker that Darth Vader was his father – but it’s actually possible that the beloved robot didn’t know that Anakin Skywalker became the feared and powerful Sith lord. R2-D2, along with the original trio, his loyal friend C-3PO, Obi-Wan Kenobi, and Darth Vader, was introduced in the film now known as Star Wars: A New Hope back in 1977, and is one of the few characters that appeared in all films from the Skywalker saga.
As the Star Wars universe expanded with a prequel trilogy between 1999 and 2005, and later with a sequel trilogy following Disney’s acquisition of Lucasfilm, some of the questions left by the original films were answered, others were ignored, and more plot holes were created. One of the mysteries from the original trilogy that was fueled by the prequels is why R2-D2 never told Luke that Darth Vader was his father, as he actually knew Anakin Skywalker and witnessed his turn to the dark side.
This question hasn’t been addressed by George Lucas, and Mark Hamill doesn’t have an answer either, but what if R2-D2 didn’t know the real identity of Darth Vader?
Star Wars Theory: R2-D2 Didn’t Know Anakin Skywalker Became Darth Vader
R2-D2 served Queen Amidala and later Anakin Skywalker, accompanied by C-3PO. Unlike the golden protocol droid, R2-D2 never had a full memory wipe, so he was well aware of all events that happened around him. 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’t even know about it.
Though R2-D2 was by Anakin’s side through his transformation from Jedi to Sith and accompanied him to Mustafar, he was ordered by Anakin to stay with the ship, so he didn’t witness his battle with Obi-Wan. When all that was over, he went back to the ship with Obi-Wan, and there’s nothing that implies he learned that Anakin survived – after all, at that point, Obi-Wan thought Anakin was dead. 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. Whether R2-D2 truly wasn’t aware of Anakin’s survival and transformation or he just chose not to talk about it again is something that will remain a mystery in the Star Wars universe until Lucas decides to offer a proper explanation.