I love this kind of “tri-fold” design, I never would have thought of it! And I LOVE the map and illustrations, they’re beautiful. Very rich locale and cool factions. The mechanics of the Ashborn and Ash Lung seem like they would be a blast in play.
I personally find the body text typeface to be a bit hard to read, and I think it would be good to bold or underline some of the key concepts and factions when they are first mentioned to imply that they will be explained later. I found myself needing to reread a few parts to fully understand. Other than that, really great work!