what if...grand duke and Duchess?

Kaedehara Kazuha, a duke from the upper nobility who is the right hand of the Inazuma kingdom, the Kaedehara clan, close to the crown prince, Scaramouche

He's mastered the art of swordsmanship, self-defense, invulnerability, and so on, many princesses and noblewomen often invite him to tea parties just to see him