In Dark Souls lore the world was unshaped, unchanging, and and covered in an endless shroud of grey fog. Until suddenly the first flame came into existence. It was that flame that created diversity or disparity in the world, changing the world giving it light and dark, life and death... It's within the flame that first humanoid creatures found powerful souls which would create the first lords, who eventually bring forth the age of fire. While it's never dis-proven it's assumed that this is first instance of the flame, and that Lord Gyn, Nito, the Witch of Izilith, and the furtive pygmy are the first to witness the flame. My question is as follows; was there ever a canon explanation as to the origin of the first flame, or what eventually sparked it into creation?
As stated in the comments, answering this is going to be rife with speculation, so I'll avoid that by saying this:
We don't know. Over the years, there has been many questions about the cycle, what the cycle meant, how to break the cycle, etc. But nothing about what created that first spark. All we know is, when it did happen, all hell broke loose.
Basically, at this point, you know as much as we do:
"In the beginning, the world was unformed, shrouded by fog. But then there was Fire."
The truth is, there is little more than that description of what happened. Perhaps it was some dude in a hole in the ground that discovered fire the same way that Neanderthals did. Or perhaps it might even be a complete new cycle of the flame, all over again - after the age of fire and dark both died out - and only ash remained for an age unknown. Who knows (excluding the devs, of course).