The black seed was a material called the seed of Heavenly Fire, which Li Tian had brought from the sun Moon continent.
To Li Tian's knowledge, if he wanted to become a divine-grade Alchemist, the seed of Heavenly Fire was essential.
This was because when refining divine-grade elixirs, the requirements for the flame were very high. The quality of one's own spiritual flame often did not reach that standard, and the seed of Heavenly Fire could give birth to a Heavenly Fire with extremely high purity.
On the sun Moon continent, the heavenly Fire was the purest flame. To become a divine-grade Alchemist, one must possess the heavenly Fire.
Even the ten thousand spirit pill served the seed of Heavenly Fire, because the function of the ten thousand spirit pill was to let the seed of Heavenly Fire take root and sprout.
