This post was inspired by a question I asked on Twitter. How do you explain clerics in D&D in a world with no gods? There were some excellent responses. I decided it was worth expounding on.
The cleric is one of the older ideas in Dungeons and Dragons. The idea of the cleric was originally a bit more like the priestly monster hunters from Hammer Horror films crossed with a crusader era European priests. The original cleric write-ups made almost no mention of individual gods. They were just nebulously holy in some manner and could cast spells as a result.