In fact, there is no such thing as a butterfly. It is the ghostly beauty of Kashin House. The book also said that this story is fiction. Similar to Cai Jun's description of "a beautiful butterfly with a goddess", it is "a butterfly with a yellow moth and yin and yang". "The Empress of Yin and Yang" is the rarest butterfly, and only one butterfly can be found among 10 million butterflies. Its wings are different in shape, color and size, and look like a grotesque butterfly. What is more striking is that its wings are female on the left and male on the right, which is very strange.

Because of the different shapes of wings, this butterfly can't fly, and its life span is 6 days. (Personally, I think: "Butterfly of Beauty" is different from "Butterfly of Yin and Yang of Yellow Moth"! )