Draining is an effect that withers its victim, reducing their power. Its exact effect varies depending on whether the target is a monster or the player character.
The following sources derive from negative energy, and can be resisted by Life Protection:
- The titular draining weapon brand.
- Melee attacks of necrophages, wights, and some other monsters.
- Negative energy damage or necromantic miscasts.
- Death curses from a mummy.
The following sources are unrelated to negative energy:
- Removing an artefact with the *Drain property.
- Remaining airborne above lethal terrain after your temporary flight has expired.
- Evoking an item with the invisibility ego (regardless of success).
- Using Formicid's digging ability.
- Ru's divine abilities.
- Hell's mystical force.
- The Zot clock running out.
Draining effects directed against the player will temporarily reduce their maximum HP. At extreme levels of draining, you could be drained all the way to down 1 HP. These drained HP won't heal over time, but will gradually recover as you gain experience until it is restored entirely. The worse the drain, the longer it'll take to work off the effect; be especially wary when fighting while heavily drained.
Late-game characters that have had the misfortune to be heavily drained may wish to seek out a relatively non-threatening side branch (such as the Elven Halls) in order to recover some of their health. Of course, gaining more experience in a challenging branch tends to remove the draining more quickly.
Being drained by at least 90% of your natural maximum HP (10% max HP left) will cause the Zot clock to kill you instead of drain you.
Followers of Elyvilon can restore all drained HP by using Purification, which costs only 2-4 piety.
Draining from the brand and spells count as Necromancy, and as such can be reduced with negative energy resistance; damage and draining are reduced by 50/75/100%, depending on how many ranks of resistance you have.
Any source unrelated to negative energy can not be resisted; even undead players will be drained.
When used against susceptible monsters, it inflicts the Drained status effect, causing the creature to function as though it had fewer hit dice than it actually does. This reduces the strength of their attacks and spells as well as their willpower, but not HP. This status effect can be stacked through multiple hits, but will wear off over time.
All demons, undead, and non-living monsters are completely immune to draining, as are any natural monsters with at least one rank of negative energy resistance.
- Prior to 0.29, the Zot clock did not drain you or check draining.
- Prior to 0.28, plant-holiness monsters were innately immune to negative energy (thus, draining).
- Prior to 0.26, draining temporarily reduced a player's skills instead of their maximum HP.
- Prior to 0.16, negative resistance lowered draining and negative damage by 33/66/100% as your resistance increased.
- Prior to 0.15, draining monsters would permanently reduce their HD, making them slightly less dangerous, reducing their XP value, and eventually killing them outright if they hit 0 HD.
- Prior to 0.13, getting drained would damage your character's experience, potentially forcing you down a level. This was permanent and was immediately lethal if you were ever reduced below 0 XP, but you could simply gain more experience to make up for it. This version of draining had no impact on your skills.