Yeah, I know I just made a blog post a second ago, but this just hit me. I can't believe I never thought of it before!
The 'battle' between Jacob and his nemesis is kind of like a game of chess, right? With the main characters being the pieces, or 'variables', as Daniel put it. Well, this would explain exactly why Jacob's nemesis needed a loophole inorder to kill Jacob.
Ready for it?
In a game of chess, a king can't kill a king, or else they'd both be in check. This is why Jacob's nemesis had to get Ben to kill Jacob for him, because he is one of his pieces. This also explains why Jacob doesn't care about Ben. It's because he's a black chess piece, while Jacob is a white one.
What do you think? Pretty cool, right?