Hit points
Player
Hit points are your life. If your hit points reach zero, you usually die. The only way of avoiding death in this case is to wear an amulet of life saving. If you are polymorphed at the time, you will return to your natural form, unless you are wearing an amulet of unchanging, at which point you will die, as normal.
More hit points are automatically gained whenever the player gains a new experience level. How much, depends on the race, role and constitution. Fighter classes, such as a barbarian, generally start the game with more hit points and receive more hit points at each new level than other classes, such as a tourist.
Hit points can also be gained with some potions. Quaffing a potion of healing or potion of extra healing if already at maximum hit points gives you one or two (or five, in case of a blessed potion of extra healing) more hit points. Potion of full healing raises your maximum hit points by four, eight if blessed.
Other ways to raise maximum hit points include "nurse dancing" (letting a nurse hit you wielding no weapon and wearing no armor), a favor ("You are surrounded by a golden glow.") from praying to your god at an altar, and beneficial effects from a incubus or succubus encounter.
If your maximum hit points are no more than 5*(2+XL) where XL is your experience level (i.e. HP <= 15 at level 1, 20 at level 2 and so on), then when you pray with very low hit points, your god will increase your maximum HP by a random amount as well as healing you. This is a handy trick to use in the early game, especially for weak characters.
Pet
Pets gain 1 HP each time they kill something or eat a corpse. Eventually, this can cause the pet to grow up, if eligible. A stethoscope is a good way to keep tabs on your pet's HP and level.
Monster
A monster's hit points is based on its level, modified in some rare cases by other things.
Normal case
hp = level * d4
An elemental on its home elemental plane gets triple its regular hp.
If a monster has a level of 0, their hp is simply d4.
Monster | Hit Points |
---|---|
clay golem | 50 |
glass golem | 60 |
iron golem | 80 |
leather golem | 40 |
paper golem | 20 |
rope golem | 30 |
stone golem | 60 |
straw golem | 20 |
wood golem | 50 |
gold golem | 40 |
flesh golem | 40 |
From the source code: "We want low HP, but a high mlevel so they can attack well"
Their hp is given by: 10d8
An adult dragon's hp depends on whether or not the player is in the endgame.
Not in endgame:
hp = (level * d4) + (level * 4)
In endgame:
hp = level * 8
Special
Some other monsters have fixed hit points. Any monster with a level of 50-127 calculates its hp by:
2 * (level - 6)
Their actual level is then approximated by:
level = hp / 4