Continuing our thoughts on what fantasy royals would do (Divine Right of Kings) ...
What are the myths about your royal lines? This is more likely one of those things you have thought about. Do they have the blood of dragons in their line? Descended from the gods? Talk to angels? Have the power of an ancient line of magic? What, besides being royalty, sets them apart from the rest of their race?
The royals and the nobles always want the people to be completely terrified of them, to know that they are different and cannot be equaled. So what stories do they tell? The myths can be powerful, especially if the people believe them. Even if they don’t, the myths serve as a means of inspiring the people. You don’t need to believe in Pegasus and Bellerophon to find them majestic or at least “cool”. Think of the art. Think of the stories and the songs.
Think too of the rivalries. Is one noble house descended from the constellation of the cobra and another use the mongoose in their crest? OK, that was too blatant. Maybe the dragon and the angels? You get the point. Sometimes the myths are used to tell the truth, when the truth cannot be spoken. Then again, it is a fantasy world. Maybe the king really is descended from dragons.
Does it matter? In a high fantasy game - absolutely! Kings with even a little divine blood should have serious advantages when trying to get the attention of the gods. Royals with dragon blood may be immune to fire. (Not all of the family as many people have seen in a popular TV show.) The noble line protected by the spitting cobra may be immune to poisons. The ideas for having a little “family magic” are countless.
Let’s take a completely different approach - TREASURE! A royal family that has been protected by unicorns will have ivory unicorn statues throughout their holdings. Or they will have paintings of the famous unicorn sightings. Or they will have silver unicorns inlaid into their gold signet rings. Or they will have whatever wood is closest to white inlaid into their tables in the form of a unicorn. Their staves will have unicorn heads. Their swords will have unicorn pommels. Let’s go with “all of the above”. I am unquestionably a fan of cool treasure, and ideas do not always just fall out of the skies. Knowing the heraldic symbols and legends of the locals gives you countless ideas for cool, artistic treasures; treasures that hopefully the players will appreciate, right before they turn them in for a boring number of coins.