So, in a world of political intrigue, power plays, and greed; I imagine that this world would have multiple villains, but more importantly multiple villains in the same plot line.
How do multiple Villains that aren't beholden or loyal to each other work? I don't want to play both parties, because try as I might, it is still hard for me to evaluate the scenario through both villain eyes, without objectively knowing that the other villain was going to do. Example: Terry Benedict in Ocean's Thirteen, where he is clearly an antagonist who is in it for himself. While this example is perhaps less influential in the plot line, it still proves the story that I think that there could be two political forces that are neither aligned with the Heroes nor each other could exist.
A second example is the anime Lord Marksman and Vanadis. In it, two Dukes are vying for power and the throne as the King lays wasting away, and they both present obstacles to the protagonists.
What should I do? Should I just play both? Or could I have another person play the other Villain? This way it is both more representative of the clash between Villains, and that while I would not be privy to his interests and motivations, I could still monitor and be part of the Villain creation, as I would still be the GM.