Story: The unnameable Prince

There is a story telling about a girl, but we're not sure it's true.
The girl in the story is related to one of the most horrible and evil man at the world.
She is lost, innocent and has no one to love. But purity is a priority.
But all what we knew from her, is that those rumors end up in a dark shade.
'Cause no one ever thought she had existed, until the rumors became a real story.