Divine damage

From NWNWiki

Divine damage is inflicted by the holy (or unholy) energy of a greater force or deity.

Clerical direct-damage spells are the most common examples of this damage type. It is especially effective against certain kinds of undead.

There tend to be few items granting resistance or immunity to divine damage. Divine, magical, and positive energy damage are the three damage types for which there is no protection via spells.