Angels and Demons

I was on the run to keep a promise of finding the others of my kind. Not many of us were left, but in order to return home I had to find the others. Together we would return home and be at peace. Only there was one problem they were coming for me. They would not give up until I was dead. With me dead there would not be a heir to the royal throne of the angels. Although it wasn't just them after me now, the demons knew that I was on Earth. For many years angels and demons have spoken of a prophecy, but never really thought much of it. What happens if the prophecy of a royal angel and a royal demon falling in love came true. Would the last of the royal angel family fall for the devils son? Or will she fall for the boy she has known her whole life?