Drain life (monster attack)
The precise effects then depend on whether it is a monster or a player that is hit.
If a player's level was one, he dies. Otherwise, the player's level is reduced by 1. His experience is reduced to the maximum for his new level. Maximum and current hit points are reduced by the same amount as they would have been increased had the player gained a level. They cannot be reduced below one hit point.
Monsters with the attack
Drain life is represented by the macro AD_DRLI.
With magic cancellation changes in 3.6.0, drain life attacks have become a little less preventable. Thankfully, most of the time you don't need to worry about it, since the first lost level is immediately regained due to the experience gained when the attacker is killed. If you expect to get hit many times, you can temporarily equip MC3 items or wield one of the drain resistance artifacts; MC3 will reduce the level drain chance to 1 in 30, which is good enough for most purposes. If you do somehow lose two levels at once, you can regain the second one by drinking a blessed potion of full healing (which will also have its usual effect).
- mhitm.c, line 991 monster draining a monster
- mhitu.c, line 1130 monster draining a player
- uhitm.c, line 1467 player draining a monster
- losexp in exper.c player loses a level
- Vampires in monst.c all V have a drain life attack
- Wraiths in monst.c all W have a drain life attack
- monst.c, line 2731 Demogorgon has a drain life attack
- monst.c, line 2554 foocubi have a drain life attack if SEDUCE is not defined
- monattk.h in NetHack 3.4.3, line 52: AD_DRLI macro