Researching is coming up empty, help please?

I'm writing a book that is basically a demon killing off gods of all religions... I know a lot about Greek 'mythology' but not really any others. Long answers are appreciated and accepted. I've tried to look up things about different ones, but it's not really doing anything. Can anyone tell me about some religions I may have missed, or don't really know anything about? umed personalities of those gods would help, also. And I do mean ALL religions. In particular, please explain Muslim, Jewish, Christianity, and Celtic. Atheists, you're welcome to chime in. Since this is for a book i'm writing, you're opinion is valued as well.