So-called spell materials are actually equipment.
Just like Li Yao's Poisonous Snake Trap. The material Li Yao uses for his trap determines the effect it produces.
The materials needed to create a metal snake, what kind of toxin to apply to the metal snake, takes a lot of thought and care.
However, Iron Stone Demons require more thought and can only be summoned using heavy plate armor or metal weapons.
But If you use heavy or plate armor to summon, the defensive power of a level two Iron Stone Demon will be ridiculously high, but its attack power will essentially be nonexistent.
But if you use a metal-forged weapon, it's different. Iron Stone Demons inherently possess strong defensive power and damage reflection ability. Combined with the attack power of the weapon, a level two Iron Stone Demon truly shows its function.
A level one Iron Stone Demon is rather useless.
