CORNBRINGER
I could interpret that Azathoth himself was Adam himself, so when the Adam incarnate woke him up, its means it was time to end his nightmares of being an outer, being chained to a father that is anything but fatherly, and afterwards only left Adam as the original Adam would be. He loves to train too much and sure being a RoB can be the most fitting prank and he even broke 4th wall just to mess with author.
Well, I am not sure what to think about the end. Many times reading stories, all these books, novels, ranobes it's rare to find really satisfying end, maybe end of this story wasn't best, bit it was pretty good. When Adam was in the temple I thought that he will become new Azathoth (I read pair of stories with this moment) but in the end he just became some kind of Divine Chimera. Well it was pleasure to read your story, wish it wasn't end but we have what we have