Generally, a Kyonshi's appearance can range from unremarkable (as in the case of a recently deceased person) to horrifying (rotting flesh, rigor mortis, as with corpses that have been in a state of decay over a period of time). It is believed that the jiangshi is so stiff that that it cannot bend its limbs and body, so it has to move around by hopping while keeping its arms stretched out for mobility. A peculiar feature is its greenish-white skin; one theory is that this is derived from fungus or mould growing on corpses. It is said to have long white hair all over its head. It is typically depicted as a stiff corpse dressed in official garments, moving around by hopping, with its arms outstretched.
It doesn't seem to remember it's previous life's memories or personality and may even behave like an animal.
It kills living beings (mostly Humans) at night to feed off their life force, hiding in a coffin or a dark cave in daytime. For such reasons, it may be compared to a mix of zombies and vampires from Western myths.
The causes of a corpse being reanimated can be classified in either of two categories: a recently deceased person returning to life, or a corpse that has been buried for a long time but does not decompose. Some causes are described below:
- The use of supernatural arts to resurrect the dead. (Necromancy)
- Spirit possession of a dead body.
- The dead person is not buried even after a funeral has been held. The corpse comes to life after it is struck by a bolt of lightning, or when a pregnant cat (or a black cat in some tales) leaps across the coffin.
- When a person's soul fails to leave the deceased's body, due to improper death, suicide, or just wanting to cause trouble.
- A victim of prematural burial (burried alive, usually when they were in a deep dead-line coma).
- A person injured by a Kyonshi may become infected and gradually changes into a jiangshi over time.