An Introduction to the Royal Guard

What happens when The Throne has hidden too many secrets within itself? What happens when the hero sides with the "villains"?
What if, they twist the hero into becoming the villain?
One can handle pain and suffering only upto a certain point. What if they're pushed beyond breaking? What if

The hero becomes thirsty for blood?

A tale of demons and vampires, eternal enemies and their hands tainted with each other's blood. Will the war ever end or are they too far gone, consumed with rage and the thirst for revenge?