What is the justification for the nobility? Some appeal divine authority. In one world however, being of noble blood really does elevate you above the common rabble. By virtue of magical aptitude.
In a high canyon in the mountains, the players find a skeleton in a cage suspended from a pole. A few miles further, they find another, and a third contains a partially rotten corpse. The fourth contains a living man who looks as if he hasn't eaten in days. Turns out to be the local way of punishing criminals.