Reading Harry Potter and the Portrait of what Looked Like a Large Pile of Ash was fun. I guess the creator must have had a detailed analysis of the original characters because I can even picture Ron doing the frenzied dance in my mind. It feels so Ron. There are many elements indicating this is not the original Harry Potter. In the original story, Harry will never say "you are a mean wizard" to Voldemort and the Death Eaters will never applaud. However, everyone seems like performing the reaction fits the character. Though the Death Eaters will never wear anything saying "Hermione has forgotten how to dance", Hermione will definitely dip their faces in the mud if they do. The whole thing feels like another universe, where there live the same characters.
Epitaph and Oilfurnace have something in common. They are both about the development of a civilization and its end. The directions of the narration are structured. Every new era is highly related to what is done in the last era. Meanwhile, they all introduce factors that cannot be controlled, like demons and explosions. The civilization stories are about inevitability and contingency, so do generative narritions.