Azazel is the Demon of War, the most powerful and ruthless member of the Twelve Knights of the Round Court of the Hades Empire. He has walked this earth for ten thousand years, feared and respected by warriors of heaven and hell. One fateful night turns his world upside down. Cursed by the last Guardian he killed, he's marked to become the Champion of the next Guardian yet to be born. Now an outcast of both realms, can he find a place where he belongs? Will he be able to obey his Guardian, let alone grow to have feelings for him?

Rai Harrington, the last Guardian to be born. Trained by the Celestial Guild and tasked with protecting humanity from the worlds evils. Being linked to a demon as his Champion hasn't been easy for Rai to accept, especially since other Guardians were bonded to Archangels. Shunned by members of the Guild growing up, he doesn't have many people he can believe in save his best friend and mentor. Will Rai be able to overcome his disdain for Azazel? Can he ever learn to put his faith in a demon? And what about all those feelings he cant control when he thinks about him?

When Rai discovers demons have been hunting for something called “The Key”, he's thrust into a dangerous race against time. To stop the threat that will be the ruin of humankind, he will have to find a way to trust who he believes can't be trusted.