Tantalum is a rare, blue-grey metal that is found deep within the chasms of Ferchiun*. Immune to all but the strongest acids, if more had heard of it would be more sought after. It is nearly as hard as adamantine and holds an edge equally as well. Those few who believed such a tale did not return from their quest to gather any, or if they did, it was not to the homes from which they came.
All spell casters gain their abilities through a form of demon possession. So in order to gain magical abilites, PCs must track down and trap demons. Of course there are some pretty powerful demons, if the demon is stronger than the PC, the PC could find themselves subjugated to the Demon's will.