Four Celestial Guardians (Azure Dragon, Vermilion Bird, White Tiger and Black Tortoise) are quite famous and widely known part of the Chinese mythology. But since equilibrium of things must be maintained, there also exist their very dark opposite - The Four Evils. Each of these holds evil characteristic such as encouraging greed, distorting truth and making wars. Some legends suggest they were born from four evil and rebellious tribe leaders after they died in ancient times during the reign of Shun Emperor. From what I found they represent destructive forces of society and ruling class of the state - or any other hierarchical group. The evil beasts’ names are often referred in Chinese language as metaphors; as you can see they are a bit forgotten but certainly not dead.
Tao Tie 饕餮
Tao Tie is the symbol of the ultimate greed that cannot be satisfied. It has a sheep’s body, tiger’s teeth and human face and hands. Interestingly its eyes are hidden under the armpits. It has baby like voice, yet it eats humans. Well, it eats everyone and everything and when all around is gone it even eats its own body. Surprisingly the patterns of Tao Tie are often found as a decoration on ancient cooking vessels in the form of its head. Expression "Tao Tie Shengyan"(饕餮盛宴) or a "feast for Tao Tie" is still often used in Chinese to indicate an extraordinarily grand banquet with delicious food.
Hun Dun 混沌
This creature is quite a mess - both of the mind and of the body. It has a shape of the huge dog, bear’s palms yet no claws; it has eyes yet cannot see; it can walk yet cannot move (strangely I know this kind of experience from my life); it has ears but cannot hear. It has belly yet with no organs such as a heart, liver, spleen, lungs and kidney and anything it eats passes through the intestines directly. More like very morbid highway inside then. It is capable of human emotions but it cannot distinguish right from wrong. When encountering noble men, Hun Dun will always have conflict with them; but when meeting evil people, it will follow their instructions without hesitation. So now you know how to call this kind of person at work, right?
Qiong Qi 穷奇
As recorded in ancient books, Qiong Qi looks like a tiger with wings. It can speak human language and is dangerously good at confusing people’s minds and starting wars with it. When it hears people quarreling, it will eat the reasonable one (and always starting chewing from the head of the unfortunate victim). When hearing about people who are loyal and faithful, it will bite off their noses. It finds pleasure in those unreasonable and atrocious and very often will offer them food. Qiong Qi is often used as a metaphor for those who act in bad faith and defame those who are showing loyalty.
Tao Wu 梼杌
This one also resembles a tiger - but after a very wild party. It has tiger’s feet, man’s face and pig’s teeth. Its hair is 2-3 meters long and reportedly it has a tail that runs more than 315 meters (who measured that this precisely is beyond me). Tao Wu is often used to label a man who is fierce, stubborn, unreasonable and unwilling to learn from his mistakes.
