Smoke King

Samuel Bachelds is a peasant, a thief, a greyblood.
Being a greyblood in a world of powerful, deadly bluebloods with unimaginable powers is a harsh life, one that millions of other greybloods have had to live.
He grew up in the run-down, war-torn village known as the Smoke, full of thieves and untrustworthy people, along with fight rings and drunken criminals. Not worth enough for the king of Iredale to give a second glance to.
When Sam's brother is convicted of a crime he didn't commit, Sam is forced to become a servant in the palace, serving the king, queen, and their young son, prince Kalisko. Along with the snobbish, eldest prince of course, to repay the fine to release his brother.
But when a strange accident occurs, revealing the powers Sam holds, he is thrown into the world of bluebloods, forced to become a pretend prince of another land, having to become the knight to Prince Kalisko, sentenced to protecting him with his life.
-
Kalisko is a blueblood prince. He'd never had a worry of the world in his life, other than a few political issues that his mother, father, and older brother had to deal with. When a greyblood with magnificent powers is forced to become his knight, he knows not what to do about it.
And then the rebels strike, and chaos erupts in the kingdom where bluebloods rule and greybloods cower.