Also, here are the comments from Joyful Steel, the angel of the edge, on what he'll need to make you a powerful enough weapon. 

The Core

"Every artifact needs a Core. A base. The heart that the rest is built around. Yours will need to be old. Ancient. Or unbreakable. Satrina is the First Witch. Her magic is primeval. Fossil wood, primal steel, a strong enough song...The bones of the earth, or the silver of the stars."

The Craft

"The Craft is the change. The heat and flux that makes one thing into another. I can manage the Craft, but I can't create it from nothing. If you can restart this forge, you'll have a chance. It'll need fuel. There used to be a planar gateway deeper in the city, but fire isn't the only option. Change comes in many ways."

The Cure

"You'll need something to cure it. To set the change and fix its shape. Water. Blood. Music. Poison. Whatever it is, it needs to pierce the heart of the Daughter of Flame."

The Catalyst

"The Catalyst is the spark. The element of enchantment. Souls. Secrets. Life. Places of power. Legends. I don't have one handy, not for something of the strength you'll need. Her will is older than the stars, and built in each of you."