Undead

Undead in Nethack are a class of unliving monster. They include all liches (L), all mummies (M), all vampires (V), all wraiths and wights (W), all zombies (Z), ghosts, and shades.

Undead take extra d4 damage from a blessed weapon. Drinking holy water also harms them; however, unholy water actually exercises their constitution.

Priests and knights can turn undead, which can make them flee or destroy the low-level ones completely. A wand of undead turning has a similar effect.

Undead are immune to life drain, such as from the Staff of Aesculapius.

Reading the Book of the Dead while cursed will summon (hostile) undead, while a blessed book will calm and even possibly tame them.