Iron Hollow

Smithing town
Giant iron tree made by a great forger in this town
There is an seedy underground organization that captures pixies and hides them in the iron tree and uses them for their pixie wing dust. Plucking their wings off which makes them brittle enough to crush into dust (Dustify)
The dust is illegal but used in forging practices to make the metal stronger and have magical attributes attached to it without having to enchant it.
Tunnels to harnsrest for material.