Goose & Gander

Since a child, around 3 or 4 years old, something has been hunting me.

I can see dark things. They are all around us, can pass through us like ghosts, pretend to be people you know.
That guy who just bumped into you on the street, your elementary school teacher, an old childhood friend. They are here, and they want this world for themselves.
All that keeps them at bay for me is a simple "X" drawn on the back of my hand. It works, believe me. Stops them right in their tracks and allows me to walk through this Life unbothered.
Other than when I sleep and the nightmares return, taking me right back to the times before I knew how to protect myself.
It's not until I meet her on the eve of my eighteenth birthday, an entire life of keeping other people away, that I didn't know I wasn't alone in the world. She is beautiful, angelic. Near a goddess than any girl ought to be.
Now the dark things are after her.
All I can do is watch as she is consumed, lured in by their power, destroyed from within.
How was I to know that nothing in this world can stop them? Other than for her to die.