Dying

Dying is the end of your game. If you die, then it is all over. You do not respawn, your game is deleted and your given a gravestone. You technically die at the end of the game, but to avoid spoilers, that is not discussed here.

Death Message
A death message tells you the reason you died. The most common death cause is losing all your hit points to a monster, however there are other ways to die.

Dying from Lost Hit Points
When your hit points drop to zero or lower, you die. It is best to keep an eye on your hit points, which can be done both in and out of battle using executed commands. If you need help understanding or obtaining hit points, click the appropriate links.

Instant Kill Attacks
The grim reaper and the end game boss are the only monsters who wield true instakill. Any time the grim reaper hits you, there is a chance that you will die outright, unless you succeed a saving throw. Liches also wield a form of instakill, their paralysis attack allows the lich an unlimited amount of attacks to kill you. However, this is not considered true instakill.

Obviously, the above monsters should be avoided when possible.

Suicide
Naming your character die or running the die executed command kills you.