The underlying logic of this world is that "yin and yang coexist and do not see each other."
The Yangjian is the real world where ordinary people live, and it is no different from the Northeast we see - 30 degrees below zero in winter, barbecue restaurants all over the street, and rusty old industrial areas. The underworld is not an independent space, but "another layer" that completely overlaps the underworld, like the front and back of the same piece of paper. Ordinary people can only see the front side, but people with yin and yang eyes or psychic abilities can see both sides at the same time.
