Distinctly odd. Worth reading, but ... odd. Don't expect comedy!
The majority of the story is a religious primal good versus evil parable - with the deeds of the evil being gruesomely described, and the good needing to be almost as brutal in order to defeat them. The background draws in everything from space aliens to mystical forces to vampirism to Satanic cults to the JFK assassination to ley lines to Nazis ...
Then we have "the final confrontation" which is over in a twinkling, and followed by an aftermath in which humanity rises and falls once again, and then a coda that's like 2001 meets Planet of the Apes. ( )