The last requirement but not the least, was a Core Stone. Core stone is the nuclei of a demonic beast. Just like its name suggests, it is their very core in which most of their powers and energy reside.
It is said that the energy inside a Core Stone is so berserk and wild that it possesses enormous risk for humans to absorb it. Even powerful practitioners, without sufficient preparations, wouldn't dare to absorb it directly.
That being said, the Core Stone is one of the key ingredients in alchemy. It might be filled with berserk energy, but when refined by an alchemist with other herbs and natural resources, it becomes much milder and easier to absorb when turned into a pill.
The Core Stones has many uses, it is not only used as the key ingredient in alchemy, but also in weapon crafting. A weapon that has been fused with a Core Stone possesses more destructive power and may even display attributes and abilities of the demonic beast the core stone was harvested from.
