Unlike cultivators, who required the Spirit Essence or other gentle and soothing energies for their cultivation, the Evil Spirits could absorb everything.
However, compared to the Spirit Essence or the gentle energies, they prefer the chaotic energies like Abyssal Essence, Demonic Essence, Bestial Essence and so on.
Also, the one in front of Ethan was not a normal Evil Spirit but an Ancient Evil Spirit and could absorb all kinds of energies with great efficiency.
As for the Blood Essence of the Spirit Beasts, it contains a mix of Spirit Essence, Blood Essence and Bestial Essence, making such Blood Essence a good cultivation resource for the Evil Spirits.
Moreover, the Blood Essence Ethan used was not from a normal Spirit Beast but a Void Beast that lives in the Void.
