Odd Thomas, Christian fiction and Devil Worshippers

I'm watching the movie version of Odd Thomas, directed by Stephen Sommers, based on the novel by Dean Koontz. Pretty exciting. Ghosts and demons, psychics and seers, Bodachs... evil spirits drawn to death and mayhem. But who are the mass-murdering evil-doers? Why, devil worshipers, of course. They have a tattoo that reads "POD" - Prince of Darkness. Neat. They kill lots and lots of people because they believe in Satan, and Satan is evil, and without God's righteous moral ...