This dream haunted me all last night and even woke me up a couple of times.
I was part of a trio of exorcists - one trio out of many spread throughout the world. Our leader was a huge, corpulant black woman who looked about fifty but was in fact much older, almost as old as humanity itself. She was the exorcist who drew the demons out of people and things. The second was a strangely vague and androgynous person whose job it was to heal the victim after being exorcised and also to heal me after I'd done my part. My part was to kill the demons after the exorcism and my hands and arms were covered in scars. All three of us could see the demons but the rest of humanity (except the other exorcism teams) could not.
Once the demons were drawn out of the victim or object they'd been inhabiting, they became corporeal for a short time, long enough for me to kill it. But bullets or blades or fire wouldn't work, they had to be physically strangled or crushed or dismembered, which was my job. On extraction, the demons looked like a cross between the chest-burster from Alien and John Carpenter's The Thing - small, strong, vicious little things with razor sharp teeth, claws and spines and covered in noxious slime. The screams as I killed them, or tried to as sometimes they escaped, were horrid.
The world was full of these demons but most people simply couldn't see them or feel them (over 90% of the population was infected) and didn't even believe in them. This situation had been going on forever, gradually getting worse, as the demons drove people to commit everyday acts of inhumanity without even realising it.
It was a very disturbing dream, or sequence of dreams, indeed.