Midgardsormr Clarification? (Spoilers)

[Sakasa]

Hate to siderail the convo but I was wondering in the grand scheme of the story is the term "King" much more then just a title? Gaius after seeing us defeat ultima questions our purpose when we have as much power as a "King". But specifically a King is a ruler but not particularly any more special then anyone else in the grand scheme as they are replaceable. He knows that as well him being in an empire where feats of not even your own merit and blood line is enough to place the crown above your head. So with Midgar using the same term to describe himself could it be that the "warrior of light" be more special then we have noticed before or is it just a catch all term for those with unnatural power.

The reason this caught my attention is because of the idea of King Arthur because excalibur while a mighty weapon also is a prophecy "as anyone who welds this sword can not die in battle" so the fated removal even though of his own accord lead to his death. Could the term "King" be set to a same tale.

I might just be reading into it to much but with Midgar in his reviving state still uses the term even though he is aware of the world around him and one of his sons are leading the dragons. It seems to point to much more then a temporary position or one granted to you by heritage.