Warning: Major SPOILERS for Star Wars: The Rise of Skywalker.
Star Wars: The Rise of Skywalker finally reveals why Rey was abandoned on Jakku. One of the biggest questions presented throughout the Star Wars sequel trilogy was that of who Rey's parents are, and furthermore why they left her on the desert junkyard planet. The question was first raised in Star Wars: The Force Awakens, when Rey had a vision after finding Luke Skywalker’s lightsaber on Takodana in the basement of Maz Kanata’s castle. During the vision we see a young Rey screaming, “Come back!” as a ship can be seen leaving Jakku heading into space with an unknown destination.
Its sequel, Star Wars: The Last Jedi, spends more time diving into the young Jedi’s past and making it a more central plot point. While training on Ahch-To, Rey is tempted by the dark side and goes under the island in search of answers. While in the mirror cave, Rey asks “Let me see them...my parents...please.” But, the mirror shows her nothing but her own reflection. Additionally, throughout the film Kylo Ren and Rey have interactions talking about her parents. During the end of the throne room fight scene, Kylo tells Rey that she knows the truth about her parents and to say it out loud. She says, “They were nobody.” Kylo follows up by saying, “They were filthy junk traders, who sold you off for drinking money.” However, this isn’t the truth.
The real reason why Rey’s parents abandoned her on Jakku was because they were protecting her from her grandfather Emperor Palpatine. Rey's father was the son of Palpatine, one of the greatest Sith Lords to ever live. Despite being related to the powerful Emperor, her parents chose to live the life of nobodies in order to keep their daughter safe, knowing that Palpatine was looking for her. Unfortunately for her parents, Palpatine sent Ochi, a Sith loyalist, to retrieve Rey. When they wouldn’t give up Rey’s location he killed them both. Although they were killed, Rey’s parents were smart to hide her on Jakku, because in the book Star Wars: Aftermath: Empire’s End it is explained that a Sith holocron is destroyed on the planet, which would help mask Rey’s presence.
With the destruction of the Sith holocron, which came at the end of the Battle of Jakku (which took place a few years after the Empire's fall), the planet was home to a Force vergence, a location (or object) where there has been powerful Force activity, which would hide Rey's own burgeoning Force sensitivity. Rey’s origin is nearly identical to Luke Skywalker’s. Luke was hidden from his father Darth Vader (a fallen Anakin Skywalker) and Palpatine in order to keep him safe. Eventually, he went on to be the galaxy’s savior destroying the Empire. Rey eventually goes on in Star Wars: The Rise of Skywalker to defeat Palpatine once and for all while also ending the Final Order, thus saving the galaxy like her master did years before.
Having Rey’s lineage finally revealed in Star Wars: The Rise of Skywalker is a relief for fans who have been looking for an answer since the beginning of the sequels. Additionally, it is a nice way to pay homage to the original trilogy and the journey of Rey’s master, Luke Skywalker. This being said, it is understandable that some may still be left with questions regarding how Rey and Palpatine came to be related. While these questions are not answered in Star Wars: The Rise of Skywalker, it can be expected that they are answered at some point in Disney's new expanded universe.