Self-Fulfilling Prophecy

Racial, ideological and cultural differences aside, the main root of the divide between mysterious beasts and cultivators had always been...benefit.

Skin, teeth, bones, organs, meat and blood, humans and Spirit cultivators had a lot to gain from hunting mysterious beasts. They could provide them with premium food to improve the talent and constitution of their juniors, materials to craft powerful artifacts, and even mounts to improve their mobility, prestige and battle prowess.

Mysterious beasts too could gain from consuming their human and spirit enemies. But said humans and spirits gained drastically more from the hunt than the opposite. In fact, due to the average human expert not being endowed with strong bloodlines, bones or overall constitution, mysterious beasts had more to gain from devouring other mysterious beasts than humans.

As for spirits, they were much more nutritious but very difficult to digest.