When a wizard named Mendalus develops a spell that summons an obedient woman named Catherine--exactly like any other summoning spell--it creates chaos in the wizard-metropolis of Meltheria, as many interested parties struggle to understand the nature (and legality) of the Catherine spell, while vast fortunes hang in the balance.
"We're nothing new. We've always been here. YOU're the newcomers. You're the animal that forgot that it was a man. Stop crying, you animal, you sleepwalker! If you opened your eyes for only an instant you would see that. You're a race of amnesiacs, of dreaming children. I said STOP CRYING! You disgust me. That's why I'm not going to explain anything else. That's why you will die--screaming--without ever having truly woken up. I will paint every inch of this floor with your blood."
-An Awakened, formerly Ms. Albright, speaking to Albert Frond, immediately before his murder
A family of semi-retired doomsday cultists, just trying to live a quiet life while tending an apple orchard in the country. Except with complications.
If you want to add a "supernatural" touch to your campaign, define the rules of magic and the universe. Make your players comfortable with those rules. Then your new supernatural creatures must then break those rules.