Bone Steel

A special steel made when burning animal or monster bones to heat iron to temper it. The carbon from the bones burning turns the iron to steel, and experienced crafters, or enchanters, can also capture the creatures essense into the steel. Bone Steel made with different creatures an have wildly different effects, but it takes years to learn how to do properly and not just end up with crumbling poor quality iron. This can be done with other metals, but is a lot harder to do.