Frozen Forge.
Materials: Vestige Ice (8 Ice), Brass Knocker (3 Force), Still Shaking Anvil (7 Steel/Force)
Appearance/Crafting method:
The head and main haft of the weapon are forged of the Anvil, producing a double headed axe blade. The Vestiges ice has been repurposed into a number of blue decorations that embody the head of the axe, held in place through the ever useful angels tears, with these showing scenes of a hammer and anvil, steadily but forcefully creating an armoury that is familiar to one that is now Lost. Brass from a melted knocker is inscribed(Engraved? I don't know words) down the haft in winding patterns that perhaps look like an avalanche rushing forwards with terrifying force.
Function:
A knockers purpose is to transfer force, and such happens here. Any attack blocked with the haft of the Forge will transfer the force absorbed to he head of the Axe, ensuring that the defender is protected from attacks. But far more important is the gathering of force to act as raw material.
Ice has no inherent purpose, yet the concept of freezing, to hold something in place, is vital here. The Channelled force is frozen in place around the heads of the Axe, keeping it steady and turning it from Raw material into something that can be shaped and used.
And finally the Anvil. The Purpose of an anvil is the Act of Creation, and so it is here, where frozen force is Reshaped into the form of Axe Blades that extend from the main body, their strength reinforced through the use of Steel. These Blades can inevitably extend to a Ludicrous Size - At maximum Capacity, the overall width of the weapon would be twice that of Fa, and given they are composed of force rather than metal, the wielder will lose no speed from holding such a colossal implement of destruction.
However, much as it pains me to admit, sometimes a Giant Fuckoff Axe isn't practical, rare as those occasions can be. Therefore, an array in the handle creates a temporary barrier between the Ice Anam and the force, using the concept of steel as a wall or shield. Though instantaneous, it destabilises one of the axe head, releasing the force held within all at once, which can accelerate a blow towards an opponent or detonate it whilst still lodged within. In this way, it becomes an avalanche, slowly building a mass of Ice and Snow, to be released in one thunderous moment.
Force is the Metal. Ice is the Flame. Steel the tools that grant it new form, and the Swings of the Axewoman the mighty blows of a Master Smith. A smithy that uses no heat - A Frozen Forge.
...god I'm filled with purple prose today.
But basically, Idea is to synergise with Fa's defensiveness in a way that reduces anam Cost, gives her an Axe that can be as Fuckoff Big as she wants, and a way for her to just
hit them really hard.
Edit: Oh fuck you van ropen, I totally thought of this first!

(Not actually mad, Your idea is neat)