Like many of her works, Mianmo's Foundational Myths of Kerofinela is (at least on its surface) a compilation rather than an original work, arranged in such a way as to give the reader a basic understanding of what the peoples of Kerofinela believed. However, underneath the surface, her Illusion Rune can be seen winking back at us. After all, we have only her word that these sources existed, and until further archeology finds any evidence to the contrary, we will just have to trust her that she did not make them up on the spot.
Whether they exist or not, she plays different sources against each other, refuses to standardize the names of the gods she speaks about, expects her audience to follow her as she stitches these stories together before and after the weaving of Time, and makes odd substitutions. Most notably, rather than referring to the Greatest Goddess, Arachne Solara (who she could not have been ignorant of, given her Lunar associations), she attributes the weaving of Time to the Esrolian goose goddess Imarja, who shares a claim to omnipotence, albeit one infused everywhere with the Earth Rune. The result is a deliberate patchwork quilt, in which what she does not share is sometimes as important as what she does.
The question remains: who was her audience? In a culture which was dominated by the oral tradition, she produced a document intended to be read. In a culture obsessed with the origins of things, she sidesteps them as quickly as possible and focuses on the dramas of the gods. In a culture dominated by the Lunar Empire, she includes subversive elements, but also a purportedly Lunar text. This translator's theory is that this was written to satisfy the curiosity of lowland Esrolia about why their northern neighbors were the way that they were, which neatly also explains the excision of Arachne Solara in favor of the hometown hero.