The Writer Became a Knight's Ward
Lilian Hayes was a college student with a budding writing career. She has one novel to her name...well, pseudonym. "Poppies of the Gods," by Rianne Riotte.
In the novel, flowers glowing with the blessing of the heavens grant those who find them the ability to use magic. People built entire institutions around the flowers. Kingdoms waged entire wars over square foot patches.
The story arc follows the young knight Liam Ward as he becomes the greatest warrior in the land, building up to his quest to find the Meadow of Light: the fabled source of magic.
Lilian was in the midst of writing a sequel when she was struck by a truck.
She is now a young girl found in the Meadow of Light, her only worldly possession a leather-bound notebook with a cliche phrase on the front page. She quickly decides that her best chance at making a name for herself in this world is to become a librarian in the leading university of magic, but she learns that the reality is more than the words published.
Muttered headcanons, edited out details, and even a random fanfic or two have shaped this world. She just made the template.