Zoroaster lived around 2000 BCE and at the age of 30, he had a series of revelations in which he saw one entirely good, uncreated and eternal God called Ahura Mazda.
Stories about the apocalypse are usually filled with supernatural darkness and suspense. And justifiably so. I mean, we are talking about the end of the world. Why would it not be scary and dreadful? This is why Neil Gaiman and Terry Pratchett's co-authored book pleasantly surprised me with their masterpiece Good Omens.