Death occurs when a character, (player character or non-player character,) reaches zero or less health. This article deals specifically with the effects and repercussions of the death of a player character.
Death occurs when a character's health points are completely depleted. The most common cause of death is usually Player vs Environment combat -- a player fighting against a mob. A player can also be killed by drowning, falling, or other environmental hazards such as lava. Note that abilities such as Life Tap, which drain the player's health, cannot cause the player to die, but may make them more susceptible to dying from other damage. It is also possible to die outside of combat due to DoTs if the player is not able to heal themself enough before death occurs.
A select few other encounters and quests in the game cause the player to die automatically.
When a player dies in any area other than battlegrounds or the Arena, they will automatically be given the option to 'release spirit' or wait for another player to revive them. If they choose to release, they will return as a ghost at the nearest graveyard to their place of death. Additionally, a 10% durability penalty is assessed on all equipped items. This penalty is based on maximum durability, not current. To revive, the player must either speak to a Spirit Healer at the graveyard, or return to their corpse in order to resurrect there at half health and mana. Dying can be a time-consuming and expensive process, exacting a penalty that is not too severe but still desirable to avoid.
In addition to reviving oneself via ghost runback or talking to the spirit healer, players can be resurrected through a variety of different means. Priests, Paladins and Shamans all have resurrection spells that can be cast from out-of-combat. Druids also have a resurrection spell, and it can be used during combat, but has a lengthy cooldown.
Shamans can resurrect themselves with the use of Reincarnation, also known as "ankh"-ing due to the component cost of the spell. Warlocks can place a Soulstone on someone to ensure they can resurrect if they die in the next 30 minutes.
There are three types of Player vs Player combat, with different penalties for each. These are World PvP, in which players fight each other in ordinary areas; battlegrounds, instanced areas set aside for PvP with specific objectives; and arena combat, where teams fight until one team is vanquished.
When killed by another player, there is no immediate durability penalty on death. However, penalties enacted by a Spirit Healer remain the same regardless of cause of death. There is an additional risk when returning to one's corpse; if the reviving player is still PvP-flagged, then any enemy character nearby can freely attack them. The player may find themselves an easy target, and might quickly die again. The practice of lying in wait for an enemy player to resurrect is known as corpse camping.
Upon dying and releasing in a battleground, the player will find themself at the nearest graveyard controlled by their faction. There is no durability penalty for dying in a battleground. Located at the graveyard is a Spirit Guide, who revives all players within a certain area every 30 seconds. Players revived in this way suffer no durability penalty, nor any Resurrection Sickness, and are brought back to life with full health and mana, (including their pet.) If the player chooses not to wait for a Spirit Guide to resurrect them, they may seek to revive at their corpse in the normal fashion. This is rarely advisable unless the place of death is very nearby and there is a long wait until the next wave of revivals from the Spirit Guide.
When a player dies in the arena, they cannot be revived, and must simply watch until one team has been completely defeated. When this happens, the arena match is over.
Note that it is not impossible to die in a fashion that causes a durability penalty to be assessed. If an enemy Priest Mind Controls you, for example, and causes you to throw yourself from a high cliff, the cause of death is fall damage and you will suffer the normal penalty. This also applies for being forced to drown yourself or jump in lava. (However, abilities such as a Warlock's Fear will not cause you to risk environmental hazards, but will cause you to avoid them automatically.)
NPCs that die will usually become a lootable corpse on the ground. NPCs die on a regular basis, and reward the players with loot, experience, quest objectives, reputation bonuses, and various other reasons. Killing NPCs in the opposing faction's towns is not often well-received. Even though all NPCs respawn after a fixed period of time, it is possible to grief other players by repeatedly killing the same NPC before they can interact with it. Some players feel this is an acceptable way to induce world PvP, other players simply view it as malice and thuggetry.
Players occasionally discuss how harsh the penalty is for death. Some argue that it is too severe and that they should not be forced to run back to their corpse or suffer a period of uselessness while they have resurrection sickness. Other players will respond that death in this game is far more forgiving than many other games, but that there needs to be some penalty to maintain death as a status that is meant to be avoided. With no real penalty to death, why would anyone ever care if they died?