Fairy/Ghost. Because that will probably show that them not all fairies are kind and cute things you'd want to take home...
...some fairies are the monsters the stories warn you about.
Fairy/Dark would have the same effect probably but I like Ghost more. --- Faust_8: Would you own slaves if you could? OW: If I lived on a farm or something, sure. But I have no need of slaves right now.
I feel like Fairy/Ghost and Fairy/Dark will lend itself to more of the non-disney-fairy-myths, like vampires, dullahan, etc. --- When life's really getting you down, take solace in the fact that you're going to die.