Antagonist

The Duke and The King

At first these two seem like some great comic relief. But then we realize they're complete, shall we say, jerks, for lack of a stronger and more inappropriate word. The king in particular is immoral, disrespectful, self-serving, and manipulative. They also put a barrier or two in the way of the protagonist's journey by selling Jim back into slavery—which is a pretty antagonistic thing to do.