Star Wars The Last Jedi: 8 Plot Theories From The Expanded Universe
6. Snoke’s True Identity Is Revealed
Supreme Leader Snoke certainly knows a thing or two about showmanship. While Darth Sidious was content to keep his holograms pocket-sized, Snoke’s fill out the whole room and show off his gnarly face in all its glory.
Speaking of his face, there are some very strong similarities between him and a certain Darth Plagueis.
It's probably best to lead off by saying that JJ Abrams has denied that Plagueis is appearing, however, you only need to look as far as the Star Trek Into Darkness Khan fiasco to decide how much stock to put into his words.
Able to manipulate midi-chlorians and, in doing so, effectively cheat death it’s highly likely that he’s still active somewhere in the galaxy. It would certainly make more sense for Snoke to be Plagueis as opposed to a random new character it was Plagueis who originally trained the Emperor, giving more emotional weight to Luke and Rey’s inevitable confrontation with him.
Not only would it make for a stronger story overall but there are other factors which support this idea. As previously mentioned, his appearance is a huge clue. Not only does Snoke look pretty much exactly like illustrations of Plagueis, it would be fair to say that after hundreds of years reconstituting yourself out of space magic time and again it’s likely you’re going to look slightly worse for wear.
Add in the fact that Plagueis was name-dropped in the prequel trilogy which means that he technically avoided the expanded universe culling and there’s a strong chance that Kylo Ren’s master will turn out to be the legendary Sith Lord.