Yesterday, I posted the mythology of a race from a science fiction setting I've been working out in my head. Since no one commented with ideas about what the setting might be, I'm going to assume that either I didn't drop enough hints (very likely) and/or people were too busy to particularly care (also very likely). So today, I'm going to explain the background for that post, both for anyone who was curious and for my own record.
The setting I have in mind is our own world, but it is at least a couple hundred years from now. Somewhere in the first hundred years, humanity entered World War III, and a biological weapon was deployed. Consisting of a water-borne virus with a long incubation period, it was designed to go unnoticed until an entire population was infected, before inducing hallucinations and ultimately a state of coma-like brain death. However, it was accidentally released into the atmosphere, and within weeks had infected all open water sources. Within a year, every human in the world had been exposed to it. Within eighteen months, humanity was effectively extinct.
But the world went on. Most mammals were unaffected by the virus, occasionally serving as immune carriers, but little else. There was, however, one notable exception to this rule: dogs. Domesticated dogs, starving and with few other sources of food, started eating the human bodies that were literally lying everywhere around them, ingesting the virus in the process. In them, the virus interacted differently (perhaps mutating in the process) to form a symbiotic relationship with the canine brain. Over the course of a few generations, this resulted in the species becoming dramatically more intelligent, to the point of sentience. The newly evolved Canis sapiens quickly became the dominant species on the planet, forming unique cultures, technologies, and at least one religion.
The mythology that I posted yesterday was the creation story of that religion - based on tales passed down from ancestors who's memories and understanding of the human part of history were blurred, at best.