Within the larger Shadowhunters universe, spanning series, the sword Cortana has been passed down in the Carstairs family for generations, forged by the first Shadowhunter weapon maker, Wayland the Smith (before the Iron Sisters, the Waylands were the weapon-makers of the Shadowhunter world). Cortana, which can cut through any material in the universe, has two edges: a sharp one and a dull one, symbolizing its punishing and merciful aspects. Short and plain, Cortana bears an inscription affiliating its material temper with Joyeuse and Durendal, which are other famous Shadowhunter swords. Thus, Cortana is imbued with legendary power.

In Chain of Gold, Cortana symbolizes Cordelia’s strength and the goodness of her soul. Cordelia and Cortana are sometimes indistinct from each other: For James, the fiery red of Cordelia’s hair and the golden sheen of Cortana represent hope and vitality. When he is drawn out of the underworld by a glow, it is unclear whether the glow was from Cortana or Cordelia herself. James’s dreams of Cordelia often feature her wielding the legendary sword. Cordelia herself loves the sword so much she refers to it as “moosh moosh-am” (429) or “my mousey-mouse” when James brings it back after Cordelia’s fall. When Cordelia performs a sensuous dance before the Downworlders, it is while wielding Cortana.