He is of royal blood and was the heir of a kingdom that was ruined, or should I say his royal family were slain and he had to escape and leave that life. So regarding his blood, he is pretty much fit to be the Empress.
But Jinshi's story remind me of Emperor Xiaozong of Ming of China, the only emperor known to have one wife and no concubine. Is the author aiming that direction then? For Jinshi to be the emperor and Maomao as the empress? Coz I support. ( ゚∀゚)人(゚∀゚ )
The MC really became Gray's salvation. ╥﹏╥