Possible Beginning of a Campaign

It gets ugly sometimes in the night.  They wait until the darkest hour before they move.  The damn things are impossible to find in the day.  We've hunted them, used our best hounds and trackers, but we come up with nothing.  Each night they return. 

Last night it looked like the night sky moved and collapsed on us.  They blotted out the moon and stars.  Silent.  Until they attack.  That's about the only way you know where they are.  The sound they make.  That god awful purring noise that rumbles through the air into your ear.  After each attack it takes a couple of hours for my ears to stop aching. 

The smartest of us have studied the wounded ones.  When we kill one they vanish into this fine dust that if you breath in will choke you to death.  The live ones are difficult to contain because they can morph their form.  I've seen them with wings, eyes, exposed organs, horrific faces and a mixture of all and more. 

The soldiers call them the Shadow.  It seems too simple of a name.  The scholars call them demons.  I can't argue that, but I think their origin is from, well, out there.  Beyond my knowledge.  I think that's why we can't find them in the day.  There is no way that many could hide.  They're hiding out there, somewhere. 

Night is coming again.  Half of us are dead including the duke.  Now we hide.  There is no defending ourselves except to hide.  Barricade the windows and doors and wait for the sun.