Thank you for outlining it like that, I hadn't even thought that they'd align like that! As for Aaron though, he's the literal antagonist of the entire world and of the gods themselves, so the author basically set the antagonist at the peak of what an antagonist can be power-wise. Which the author then has trickled down throughout the story, only showing small amounts of the total amount of power that this ultimate antagonist represents.
So any kind of follow-up to that ultimate antagonist, is not likely. The story will probably end once Aaron is defeated.
As for the questions you pose, there
are hints in the novel already that can probably answer them. I can't say anything about it without spoiling things, so you're gonna have to keep reading to find out (or read the novel up to where it's at now).