The practice of secondary world building, the creation of a fantasy realm with its own unique laws and systems has long been a tradition within the genre of fantasy writing. In many notable cases, such as those publications by J.R.R. Tolkien and H.P. Lovecraft, folklore exhibited in the world of the reader has been specifically used not only to construct these fantasy realms, but to add depth and believability to their presentation. The universe of J.K. Rowling’s Harry Potter series demonstrates this same practice of folklore-as-world-building, yet her construction does much more than just create a fantasy realm. By using both folklore which predates her writing as well as created elements which while unique to her secondary world specifically reflect the world of the reader, Rowling is able to create a fantasy realm which is highly political, complex and multivocal, yet still accessible to young readers through its familiarity. Specifically through her use of cryptids, belief representation, and folk narratives both invented and recontextualized, Rowling is able to juxtapose her fantasy universe to the real-world of the reader, in effect inventing a believable secondary world but also demonstrating to young readers the ways in which her writing should be interpreted.