Nancy Holzner, author of Deadtown

will give glimpses into the demons, her character Vicky Vaughn will exterminate on her blog, There are three main kinds of demons:
Drudes: Dream-demons that cause nightmares so they can feed on the victim’s fear.
Eidolons: Guilt demons.
Harpies: Revenge demons. People sometimes pay sorcerers to conjure Harpies and send them against their enemies.

Nancy is also compiling these post at Deadtown 101 where she gives you a glimpse into Welsh Mythology: The Mabinogi