See also: Demonology, Gods and Celestials, Magical Bulbs, Roots of evil.
Demons are just as sentient beings as deities and gods. They are not inherently evil, nor are they necessarily good (the same can be said about gods). However, humans usually depict them as evil, often due to the demons’ inherent selfishness.
Demons reside in the Under Realm, from where they can breach into other realms. Like deities, demons do not possess mortal bodies; they only possess celestial forms. In order to remain in the Earthen Realm, they require a body or a sacred vessel, much like the gods.
Demons are driven by primal, animalistic passions. For instance, weredemons are always hungry, angry, and greedy. Demons are born from the depths of human passions, from the ‘three roots of evil.’ These passions cannot be completely satiated; they can only be dulled. Hence, passions guide the actions of demons.
Demons are creations – creatures that were never born. They crave mortality and, at the same time, cannot endure it. Therefore, they cannot stay in the Earthen Realm for long and destroy the bodies they possess. Their insatiable thirst for death fuels their hunger, anger, and greed – especially towards mortals who possess what demons can never attain.
When demons manifest in corporeal form (typically by possessing someone’s body), they take on a bestial shape, such as giant bears, wolves, badgers, and so on. They appear as a blend of human and animal, akin to werewolves.
One can envision weredemons as animals that have escaped from Heavens. They always assume a bestial form and give themselves animal names, such as Brother Leopard or Brother Jackal.
As if that wasn’t enough, the demons ganged up on people like stingrays on krill. In an instant, they crushed even the largest empires and kingdoms, then began to exterminate the human race in its entirety. Starving demons swallowed whole villages, and from this their gluttonous hunger only grew.
Having possessed the monks, the weredemons began to change shape. Long claws protruded from their hands, and their mouths were filled with pointed teeth. Hair appeared on their once cleanly shaved heads, and their ears stretched upwards. The skin of one of the former monks turned green, while the second one’s skin turned blue like a tuna, and became covered with spots. Quickly, they no longer resembled human monks at all – now, they looked like wild beasts.
The weredemons escaped the now-broken bulbs and jumped into the first person that got in their way – a portly peasant who was sitting next to the largest cow with a bucket at his feet. The peasant intended to milk this cow, but instead he fell to the ground, arms outstretched. And the demons, now having his power at their disposal, possessed the three cows standing nearby.
The cows’ legs splayed out and their hooves sharpened. They roared loudly and, shaking off their fetters, rose to their hind legs. Their front legs turned into hands, but instead of fingers there were still hooves.
Following the travellers crept a weredemon, whose name was the Flying Fox. He did not look like a fox at all, and his appearance resembled a cross between a bat and a forest squirrel. Sharpened claws protruded from his leathery wings, helping the demon jump from tree to tree, to hide from the attentive glances of Sung-Guan and the bored gaze of Zhu Leizu.