A thought: Emperor Thrawn.
During Treason there is a scene where I believe it is Ar'alani is questioning Thrawn's loyalty and makes a comment about him taking over the Empire in Palpatine's stead.
Then in the Acendancy books, Patriarch Thooraki makes a comment about Thrawn being meant to lead something greater, maybe even the Acendancy.
This is all from memory so I'm probably wrong on the exact quotes, but it would scream worthy if Thrawn was the Emperor. I know logically, he would never because of his aversion to politics, but still...he would be so powerful.
I'm going to make a collage of all of the references that I can find.