Guard me (Sebaciel fanfiction)(Kuroshitsuji Black Butler)

Small hands buried themselves in the Ravens hair and lightly knocked the crown that he was wearing. The incubus was desperate now. Oh, how he wanted the king at this moment in time.
But, his own moans cut him off, what was the general doing?
Ciel was of the military, he was not allowed to kiss a king, especially if said king was to be married. Somehow, the boy was able to rip himself away from the man, glaring At him, but also looking slightly scared.

"I can't. My liege. I'm happy that I have found my bonded and I'll forever be grateful for it.
However, you are a king- a soon to be married king- and I am a guard, a man- I can't produce an heir! I must just treasure these moments." Blood soaked tears threatened to fall from Sebastian's eyes; here a great king was, about to cry in front of someone. But, it really wasn't just anyone he was about to cry in front of. It was the one person in the world that quite literally held his own life in their hands. With one hand reaching out the demon pleaded with his carmine eyes, "Please Ciel. Don't-"

He stopped once the incubus turned back to human form, body back to normal and slightly scratched and much much smaller now. This was Ciel.
And Ciel took another step away, then bowed.
"I look forward to protecting you your majesty. I shall place my life on the line to serve you and look after you. You have my word, and promise, a solemn vow that is the word of a demon and general."
And with that, Ciel disappeared from the roof.
Leaving the king standing alone with a down sodden expression.

Their love is taboo, wrong and sin. What will happen in the labyrinth that is known as 'Guard Me'