Rey is a Palpatine. It sounds like some Jar-Jar-is-a-Sith-level crazy when you first hear it, but there’s some pretty compelling evidence that is folded into that movie, beyond the obvious “she must come from a force-strong family” and “her origin is important” business that can be used to support most other fan theories. Here’s what I got.
https://www.huffpost.com/entry/this-bizarre-star-wars-theory-palpatine-_b_9617828