In ancient times humans and demons shared happiness and worked together as one
with each other, but it was broken when humans began to feel that stealth was
dangerous and demonic creatures think humans are weak creatures, then
A fight arose between the two of them, so many died
killed. Among those still alive are the fox clan and the human clan who call themselves demon hunters.

The two clans ultimately reached an agreement to live side by side until they existed
who started a relationship, but it all left both of them hurt.