The Devil Race is an ancient race that ruled half the universe (Northern half) along with the God Race (who ruled the Southern half). While there were mutual hostilities, both sides rarely interacted with each other. It could be said they were living in peace by ignoring each other's existence.
When gods fall and leave behind their inheritance, their left behind blood essence or soul fragments will receive protection and affection from the natural world. But it's different for devils, whatever they leave behind will slowly be extinguished by the natural world because their yin energy generally gets rejected.
Shortly after the demise of the gods, there indeed were inheritors of the devil race, but those demonic energy will soon be exhausted and purified by the natural world after a couple of generations.
- Fen Juecheng is most likely from a clan who are descendants from the Devil Race, as they have Devil Blood inside of them.