Secondary world
A secondary world is a self-consistent, culturally established fictional world in Hesanic literary culture. Works are written about the secondary world as if it is "another real world", in a sense. As a result, Hesanic literature is not divided up as nonfiction vs. fiction, but along two axes: one being the world it's in (Yona (the real world), Durzir, the Delta Rune world, etc) and the other being the type of book (law book, narrative, history book, "fun fact" book, etc). There are a relatively fixed, small number of secondary worlds in the cultural consciousness at any given time, often associated with microvariations in culture. As a result, it's often easy to confuse Hesanic fiction for non-fiction for someone unfamiliar with the culture.