On the Empirical for a completely different project, and as an easter egg to boot. According to just about every single piece of evidence available to us at this time, the Starkiller controlled by the player in this game was cloned on Kamino. Even if he isn't, however, that's not relevant to this update; it neither confirms nor denies that Starkiller's the real him. What it does confirm is that clone or not, the player plays as 1138.
As for 1157, it's clear at this point he was a red herring; he's another one of the unstable clones who gets killed by 1138 either when he breaks out or later on, "if" he returns to Kamino.
"Grant Allen [...] had written a book about the Evolution of the Idea of God. [...] it would be much more interesting if God wrote a book about the evolution of the idea of Grant Allen." ~ G. K. Chesterton, The Everlasting Man