Lothian: "1 Don't worship demons, you lose your soul if you do. 2 Gods may actually be demons who pretend to be gods. 3 I know I am not a demon. 4 Therefore I'm the only god I can vouch your soul will be safe with. 5 I have a duty to protect human souls from being devoured by demons." This is not really an argument for a worshipper to move to Lothian as the worshipper cannot verify Lothian's point 3. It is an argument for Lothian to want to have people worship him exclusively.
Ok, now I've so got to come up with a setting with a God that holds this philosophy and in fact is the only god who is a demon somehow but doesn't know it himself.
Thanks' for the inspiration