mechamaster73
Yeah, it's well known fact that Sith can alter their appearance. Somehow Palpatine managed to discover it. The only place where such detailed information about the Sith would exist is at the Massassi Temple, Korriban, or the Jedi Temple, which is the most accessable of the three. Unless he were once a Jedi, in which case going to all three places would be quite easy and go unquestioned, it would be difficult for him to have learned all his Force abilities. I know, I'm being stubborn about this, but I'm just trying to show that upon careful examination all signs point to him being Sifo-Dyas.