Lin Mu had heard of the Hong Lin tree resin before. It was harvested in the winters when the trees let out their sap and only those that were over a hundred years old produced this resin.
It was used to make ink, which was used in the creation of talismans and other formations. While most of the formations could be made with spirit Qi as the ink and spirit sense as the brush, the direct method of using actual ink and brush was also quite popular.
In some cases, that was the only way to make several formations that were above the capabilities of one's cultivation base. Many formation masters who had great skills with formation but were restricted due to their cultivation base used this method.
The ink used to make these formations and talismans was made by mixing and processing several materials. There were an almost endless amount of combinations that could be used, which led to several different formations.