The Runes are the building blocks of Glorantha. They are symbols, archetypes, embodiments, and the actual matter and energy of the world. Runes originated with the very creation of Glorantha. The Runes are more than just written symbols. When a Rune is written or inscribed, the real power of the magical image is present within it. Repetition of a rune does not weaken it, but strengthens its presence and firm reality in creation. Their precise origin is unknown, and followers of particular runes always insist that theirs was first-made. Tales link the gods of the Celestial Court with the Runes, each god embodying a Rune. Their interactions led to the births of the Young Gods; these newer deities are often associated with one or more parental runes as a result.

Each Rune has myths associated with it. Some have elaborate cycles woven around their stories. All begin with a member of the Celestial Court who owned the Rune, and end with the Great God who currently owns it. In these stories the runes are sometimes treated as things, or beings, or abstract powers, or even all three.

The powers of the Core Runes are universally acknowledged. The deities who command those runes are the Greater Gods. Those deities cannot be changed without altering the very fabric of the universe. Such alteration is against the Cosmic Compromise which begat Time, and cannot occur.