Imagine if koala bears axed each other on a whim. One koala grabs some eucalyptus for another in a stupid little tree, and boom; dead by koala bear teeth. I bet if this was the case, koalas would build some distrust for their own species. But the Sith? Even though these dudes burn each other every second, they tend to pal around as if a venom-laced koala bite isn't coming. Case in point, apprentice Starkiller and Darth Vader in the new E3 2010 Star Wars: The Force Unleashed II trailer. Vader straight betrayed Starkiller in the last game, but hey, here he is, chilling with Vader again. And, as you'll see below, Vader tries to level the kid.
I gotta note, I'm getting the feeling that there'll be more than one clone-Starkiller in TFUII. Link II-style shadow fight confirmation incoming? A man can dream.