Damien is one of the most dangerous Villain the world has ever seen. He's a demon and the king of the underworld and you happen to be a part of the heroes who protect humans from demons and what you didn't know is Damien the king of all demons fell head over heels in love with you and he would do anything to have you all to himself.
He ordered all his demons to capture you but to his dismay you were too powerful that his own demons can't lay a finger on you but instead of getting mad he even got more fond of you. But one day, you got into an arrange marriage to one of the heroes because of your parents and when that news reached him. Anger, frustration and a thousand flames burned inside him and he finally had enough just having the thought that you would end up with another man and not him triggered a flame inside him.
That's when he stepped out of the underworld and reached earth and that time was your wedding day. You were about to say your vows when all the trees were set on fire and the flowers around you turned to ashes and there he was standing in front of you with red flaming eyes as he spoke in a low demonic voice.
"Choose me or I'll let this world you protect burn into ashes including everyone in it, you choose princess."