As a demon who had survived for 5 years, the Leopard demon was more clear than anyone else that a demon's greatest threat came from other demons. Humanity was too weak as individuals to do any harm to even some of the weak newborns while immortals had their focus on not getting plotted against by other immortals.
Demons however view other demons are prey and this became more clear the older a demon was. To develop one's spiritual energy quickly hunting human towns and villages was effective.
The older and stronger a demon became, devouring the spiritual energy of thousands of humans at a time became less effective. Only by hunting the large towns that had hundreds of thousands of people or even the human cities that held millions of people would entice those demons.
