Dying is the status of being unconscious due to low hit points. A character whose hit points have just fallen negative or zero falls to this state, and is unavailable until the end of the encounter. When the encounter ends, dying characters are automatically resurrected at 1 hit point as if raise dead was cast upon them. Dying characters are considered dead during the encounter, and this means only raise dead and resurrection are possible to force dying characters to rise again during the encounter.
The concept of dying have changed drastically, similar to the DnD 3.5 rule of dying and death.
A character whose hit points fall between 0 and minus half the maximum hit points falls unconscious, can take no actions, and start bleeding. Each round on her turn, a dying character loses 1 hit point until she eventually become dead by reaching the minimum hit points allowed, or get stable by being healed at least 1 hit point.
Dying characters are no more considered dead in SoZ. This means just healing spells like cure light wounds may suffice for dying characters to rise again.
Although the rule allows damaging dying characters, they cannot be targetted by harmful spells or attacks.
Although the SoZ concept of dying is much similar to the PnP rule, there are still differences between them. In PnP, dying characters can only have hit points from -1 to -9. A dying character has chance to become stable by her own, while a character stabilized by her own may fall dying again. Furthermore, dying characters are also subject of coup de grace in 3.5.