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Just read an interesting theory thought I would share it. Rey is Luke’s daughter but Kylo was the one that left Rey on Jakku. In the vision, one of the Knight’s of Ren was about to strike Rey down but then Kylo killed him. The vision then transitions to Rey being dropped off on Jakku. It makes more sense that Kylo was the one who left her there. He likely wanted to protect Rey, she being his cousin, from the other Knight of Ren so he dropped her off on Jakku, a middle of nowhere planet. It is also more plausible that he would leave her with the scavenger lord than her father would. He has a talent for mind manipulation using the force so he could have done a mind wipe on her, something we haven’t seen done by any force users like the stopping of a laser blast. He could have done it to protect her, prevent her from reaching her full Jedi potential, or both. Luke, Leia, and Han would have thought she was dead like the other younglings, that’s why they never mention her nor recognize her. That along with the loss of the other younglings and Kylo’s turning was why Luke went off to the Temple. Further the grave at the Jedi temple was either for Rey, her mother, or both. Leia could have recognized Rey after she used the force so much on the planet and that is why she passes up Chewy and gives Rey a hug after the death of Han. This seems the most plausible right now, at least to me.