The King and His Knight

Dean and Castiel were the closet of friends when they were little and naturally Cas and Dean thought they would be able to be best friends forever with no issues.
And it was that way for a little bit,
until Dean's parents were horribly slaughtered one night and Dean is forced to become King.
With Dean busy with planning a wedding and running a kingdom, Castiel decides to follow his dreams once and for all and become a knight.
But when Castiel returns he finds that some very big changes have overcome the palace and has destroyed all chances for Castiel to be with Dean.

Or has it?