Monster x Reader: Loyal to the King, Never to the Kingdom

You are the spymaster to the King of all Kings, and the power that hides in his shadow. You have taught him, protected him, and suffered seven years of pain at his hands; despite the scars he inflicted, you remained his shield in the dark. Warding off his enemies and stoically, irrivocably loyal to the man behind the throne.

When his behavior toward you rapidly changes, you are left to rediscover the man you knew all those years ago and rekindle the tension you had never once acted upon while in battle.

Even if he is no longer a man at all.

(This is a reader insert in what I would like to call the badass royalty vein of fantasy. Also posted on AO3 ).