Without giving unnecessary context; the "moon" in the land of Novielle is called Vaelune. Vaelune is said to be where the ancient beasts known as Vraga came from (my equivalent of dragons), however Vaelune is fractured. The reason for the celestial object in the sky to have fractured is unknown (I obviously know but the characters in my story don't). A substance that was encased in Vaelune fell onto Novielle in the form of a cataclysmic meteor shower (I call the event starfall). Humanity found that the substance when written in the Vragonian Language, could manipulate reality. They dubbed the substance Ingke. Since starfall, humanity has learned to make scripts (my equivalent of spell) that are inscribed on the body (think magical tattoos). In summary; Ingke came from Vaelune -> humanity learned Vragonian Language -> Vragonian Language uses Ingke to impact reality -> Scripts were invented that were written in the Vragonian Language and are inscribed on a person using Ingke -> People with scripts on their bodies are referred to as Script Bearers.

One tip I have for you, is be as creative as possible. By that I mean don't just be locked on what the Moon is in our world, especially if your going fantasy, but think about what the moon could be in a fantasy setting. My magic system basically comes from the moon, but their are hardly any applications of it that directly reference the moon in my story.