Jiang Yu, a nine-tailed fox with the purest bloodline in the fox demon clan for thousands of years, only took a thousand years to cultivate to the realm of the demon king. He yearned for the human world that the fox emperor told him, so after entering the demon king realm, he came to the human world and met the prince of the demon world who had come to the human world to experience. He accidentally killed the prince.
So the pattern of falling in love and killing each other started.
Purpose: The nine-tailed fox is a protected animal in the world. Protecting animals starts with you and me.