Iron of Acheron

Iron of Acheron is a blackish-green metal said to originate from chips of Acheron itself falling through portals to the Material Plane. It can be forged into blades by mortals, though it is difficult to work with due to the inherent infernal poison stored within it. However, this poisonous property makes the resultant weapons particularly deadly.

Bane of Arachne, a dagger created in the Elven Swordmaking tradition by Master Kento, is an example of a blade made with iron of Acheron.