In this world, other than Cultivators, there are other types of cultivators. They are:
Evil Cultivators: After the Evil Spirits successfully possess the Cultivators, they become Evil Cultivators and follow the evil cultivation to become stronger.
Demon Cultivators: The Cultivators who, due to limited or low cultivation talent, give up on the normal cultivation and follow a Demonic Path where they would be transplanting the Spirit Roots, using body organs and blood, following the Demonic Techniques to become stronger.
They were hated by the humans and on the other hand, they were greatly respected by the demons because these Demonic Cultivators have the brains of the humans and the strength of the demons.
In short, the Demons feel that these Demon Cultivators are greatly useful in taking down the humans and obviously, the Demon Cultivators have been in cahoots with the Demons in taking down the Human Race.