Ancient metallurgy
It's all very dramatic showing the crucible of molten metal poured into the sword-shaped mould, and later being poured over Ron Perlman, but you just can't make a sword that way.
In ancient times they could scarcely ever achieve a high enough temperature to melt iron, and if they did all they could produce is cast iron which is too brittle to make a sword (and is always cast in sand, not a rigid mould).
A sword is make by forging steel from iron ore by heating, hammering, bending, multiple times.