Knights or princes are the spirit of the teenager, all about changes, movement, action. Knights are never still; as the pages/princesses suggest messages, the knights suggest travel and spreading what they know. They are also, as Knights, about engaging in battle.
Elementally, they are Air moving and flowing. As a person, they're likely to stand for a young adult or someone who acts very like a teen. Their beliefs are purer than of an adult, less cynical, more fierce. And like their element, they are prone to argue and fight for what they believe. In this they are most knight like: powerfully, almost unquestioning loyal to a kingdom or cause.
Learn the Knights meaning in reversal in our reversed card meanings.