Question: how are rey and kylo ren related?
Answer: It's revealed in The Rise of Skywalker that Kylo Ren isn't the only powerful Force-wielder with an equally powerful parentage: Rey, formerly the child of no one according to The Last Jedi, has been revealed to be the grandchild of none other than Sheev Palpatine, the Emperor and resurrected leader of the Sith. Yep.