Poison

Poison has many harmful effects. A poisoned weapon is capable of causing poison damage, whether you or a monster is wielding the weapon. Certain kinds of corpses are also poisonous, and damage you when you eat them. To protect yourself from poison, obtain poison resistance.

Effects of poison include:
 * Reduces your HP.
 * Reduces your strength.
 * At a random chance, causes your instadeath. Poison can be fatal.
 * Any others?

Routine contact with poison at the beginning of the game will reduce your strength, thus limiting the weight of your inventory. You want to find a unicorn horn (not cursed!) and apply it repeatedly.

There was some restriction on certain characters using poisoned weapons. Was it something about lawful gods?