As a follow-up based on SPOILERS that I just read in another thread...



Apparently the Jedi Knight kills the Emperor's body, but his consciousness had time to transfer to a new body. Supposedly the Jedi Consular is responsible for the ultimate "banishment" of the Emperor's spirit / consciousness / whatever term you prefer.

Some people might say that that opens the door to Vitiate later being Palpatine, but I still think that's highly unlikely based on what is currently known about Palpatine's youth.


EDITED TO ADD:

GCRust, based on what I just said above, it's possible that BioWare is keeping the door open to Vitiate returning in a later content update - a la Palpatine returning in "Dark Empire" after his death in Return of the Jedi.