Fan Casting Good Omens

Good Omens is a novel about the apocalypse co-written by Terry Pratchett and Neil Gaiman, in which The Antichrist is accidentally Switched at Birth and given to a normal family, where he grows up free from any influence of Heaven and Hell and becomes a completely normal and average child. Well, normal aside from the fact that he's subconsciously using his powers to make sure his small, quaint hometown stays small and quaint... The mix-up causes plans for Armageddon to spin wildly out of control, as agents of both Heaven and Hell try to find out just why things aren't going as planned. Two of those agents, an angel (Aziraphale) and a demon (Crowley), who've come to realize that they have more in common with each other than with their superiors, are trying to find the Antichrist and put a stop to The End of the World as We Know It because they decided they like humanity. Also in the mix are the last witch-finder in England (and his new assistant), and a modern-day witch who is the heir to a book of oddly specific but still conveniently obscure prophecies.