The Star Wars sequels failed to fully address the mystery around Supreme Leader Snoke, but The Rise of Skywalker (and its novelization) essentially confirmed that he was a cloned body Emperor Palpatine had created in order to manipulate Ben Solo and the First Order. On Exegol, we could even see that there were cloning vats full of "failed" Snokes.
There are big parts of that explanation that don't make a whole lot of sense when you stop and think about it, but even The Mandalorian hinted that Moff Gideon wanted The Child in order to create a new body for the Emperor. One possible reason the villain planned to return as a new being is that he couldn't face the Galaxy knowing about his defeat; unfortunately, until Lucasfilm provides some answers, we're left to speculate.
What we do know is that one successful clone managed to escape from Palpatine and ended up having a child who would ultimately defeat the villain. That makes Rey a Palpatine and both the Emperor's daughter...and grandaughter? It's a weird one, but an interesting new wrinkle was added in the pages of Darth Vader #11 yesterday.
When the titular Sith Lord visits Exegol, he finds a massive Kyber Crystal that's being used to power what would ultimately come to be known as the Final Order and a series of cloning vats. One of them contains a hand that, as you might expect, has left many fans convinced that it must belong to Luke Skywalker after Vader sliced it off on Bespin in The Empire Strikes Back.
It's hard to imagine who else the hand could belong to, and this could be an indication that Palpatine has either cloned Luke or used his DNA to create Snoke and his other doubles. If that's the case, then Rey could have some Skywalker DNA in her, a twist that might justify the whole "Rey Skywalker" twist.
Here's hoping this is eventually elaborated on, eh?