You know the Christianity of two thousand years ago, if you could call it that back then, was still debating on there was even a devil and where souls went if not 'The Kingdom of God'. A lot of what it is today developed over centuries. It's this developed way of thinking that built over centuries by tons of thinkers. Knowing that, I doubt Christianity would exist in this time as it is today. Scorching most of society means losing a lot of the diversity that's kept Christianity alive. For example, if only Americans survived, most of our population isn't actually very educated about the deeper rituals or theological understanding of the texts. You'd have this religion that survived solely on the understanding of those left, then jump centuries and it's probably changed even more.

I'd be interested in seeing some characters holding on to very old ideas. Imagine those religions that were never too different mixing up together, like Islam, Judaism, and Christianity just merging into this Followers of God thing. 

My plan with Guamá is to pull from the Taíno Arawakan culture, something I have a real connection with, while mixing it with some aspects of old Judaism. What about y'all?