The Demon Essence Pill can enhance Di Shen's cultivation when his soul is incomplete, but the conditions for refining the Demon Essence Pill are extremely harsh.
First, one must have at least Fang Venerate Level cultivation, secondly, one must possess a treasure cauldron with all Five Spirits, and the final condition is to have a Demon Soul of at least Great Demon Level.
When Ye Lingyue learned about this elixir from the Shishen Refining Cauldron, she had always wanted to refine it for Di Shen.
However, at that time, after arriving at Qing Province Continent, the demon beasts on the mainland were too scarce, and Great Demon Level Demon Souls were even rarer. Moreover, with the Demon Awakening Gate sealed, Ye Lingyue had no way to refine it.
It wasn't until arriving in the Ancient Nine Provinces that the conditions became available.
