Warning: If you still haven't seen 'The Force Awakens' you might not want to read this article, unless you don't mind spoilers.
All right, let's do this!
If there's one thing I love about the Internet it has to be all the fan theories you can find here. There is something for everyone, whether you believe the family from Home Alone is a cult, or that Snape was the one who killed Hedwig, the Internet is here and ready to provide. But the one fandom that is providing the most amount of fan theories these days is by far that of Star Wars.
The question of Rey's origins was widely speculated before The Force Awakens came out, and since the movie didn't really give it away, the theories have kept growing. Many people believe she is Luke Skywalker's daughter, while others are crossing their fingers that she's somehow related to Obi-Wan Kenobi. A recent theory, originally posted as a YouTube video by manyymedia, suggests that Rey is actually the reincarnation of Anakin Skywalker, and her role is to bring balance to the Force.
So what evidence is there to support this claim?
Well, first of all there's the lightsaber. Once owned by Anakin, then passed down to Luke, it somehow ended up in Maz Kanata's basement where Rey found it. Or rather — it found her. Anakin's lightsaber was calling out to Rey, as if she were the rightful owner. This led many to believe she is Luke's daughter, but perhaps... she is his father. Déjà vu, anyone?
The next piece of evidence to support this theory is how similar Rey and Anakin are. They both lived on a desert planet, they're both skilled pilots and mechanics, and they both treat droids with respect.
The Force is unusually strong with this one
Rey is surprisingly talented at using the Force — despite the fact that she has no training at all she managed to withstand Kylo Ren's mind reading. She's never used a lightsaber in her life, but she managed to beat Kylo Ren. In fact, when Kylo offers to teach her the ways of the Force she repeats "the Force," and it's like she enters some sort of trance which ultimately leads her to defeat him. Could she be remembering her past life?
Anakin's personal purgatory?
Anakin grew up as a slave on a desert planet, so it's safe to assume he has a particular hate boner for sand and deserts. Luke was raised on a desert planet too, although perhaps to ensure that Darth Vader would never find him there.
Another thing we need to remember is that Anakin was a family man. Everything he did was to save his wife, Padmé, and their children, even if that meant turning to the Dark Side.
The theory suggests that Anakin was reincarnated as Rey, who grew up on a desert planet without a family, and that this is supposed to be his own personal purgatory. The time has now come for him to redeem himself and bring balance to the Force. You could argue that Darth Vader did redeem himself at the end of Return of the Jedi when he killed the Emperor and saved Luke — but 30 years later the Jedi are a mere myth, no one knows where Luke is, and a dark force is threatening the galaxy.
Did Rey see Anakin's memories?
When Rey touched Luke's lightsaber, she had various visions and flashbacks. The first thing she heard was Darth Vader's breathing. She then proceeded to see Cloud City and a lava world. According to the theory these are Anakin's memories she is seeing. Or rather — her memories.
The conclusion to the theory is that The Chosen One is not just Anakin, but a being who is reincarnated. This time Rey was the reincarnation, as a punishment for the crimes committed in her past life. Just like Anakin, the previous reincarnation, Rey has visions of the future, she is very powerful with the Force, and the time has come for her to redeem herself and destroy the Empire she helped create, to save her grandson from the darkness, and to finally be able to see her children.
In the prequels we saw The Chosen One fall to the Dark Side, in the original trilogy we saw him return to the Light and in the new movies we will see The Chosen One fulfill his/her destiny and save the galaxy from the darkness.
I know this is a lot to take in, so if you want to go through it one more time I recommend watching the original video, as it goes into more detail and you don't even have to read: