The Gryphon Knights are the commanders of the Sovereign’s Finest, the King’s loyal advisors and bodyguards.
The Sovereign’s Finest is The Crown’s Personal Unit. They are not only elite fighters who have distinguished themselves in service to the Country (Caladania), but they are trained to be envoys of the crown and capable of special duties.
Sovereign’s Swords are the distinctive weapons of the Sovereign’s Finest, the upper ranked members of the Kingdom’s forces. These special agents are the Sovereign’s hands, imparting justice and rulings when needed, being embassy, or doing special duties.
The ruling family depends on some magical artifact or place to secure their right to rule. A monarch isn't considered legitimate until he or she has been "accepted" by the artifact or place, whatever that might entail. It is also possible that some one else, not of the ruling family, could be accepted as the legitimate heir... A fact which the monarchs would like to keep secret.