Cortana is a very special sword forged by Wayland the Smith. The
words “I am Cortana of the same steel and temper as Joyeuse and Durendal” (sorry if that’s spelt wrong), are engraved in the blade. It was passed down through the Carstairs
family for many years and currently resides with
Emma Carstairs, a badass Shadowhunter warrior that deserves the world. Cortana is known for sometimes choosing who wields it. For example, in Chain Of Gold, Alastair Carstairs wanted it and his
father, Elias, agreed that he could have it, but suddenly Cortana flew(? idfk) through the
air and into the hands of Cordelia Carstairs, another badass Shadowhunter warrior that also deserves the world.