Most of these descriptors have no game effect by themselves, but they govern how the spell interacts with other spells, with special abilities, with unusual creatures, with alignment, and so on. eg. A mind-affecting spell works only against creatures with an Intelligence score of 1 or higher. A creature immune to fear is immune to all spells with the fear descriptor.
It is also helpful for roleplaying in the NWN2 game engine, as in DnD 3.5 no good-aligned cleric would ever cast a spell with an evil or negative spell descriptor, and while the game engine does not enforce this it makes it easier for those wanting to abide by such rules.
Confirmed NWN2 descriptors:
- Weapon enchantment
- Armor enchantment/Magical armor
See also: Subschools
DnD 3.5 comparison
- 3.5 ruleset also includes: air, chaotic, earth, good, language-dependent, lawful, light, and water.
- 3.5 ruleset does not include: divine, negative, poison, disease, weapon/armor enchantment, paralyze, gas, figment, compulsion or healing.
- Many of the NWN2 descriptors are subschools in DnD 3.5 and function in a similar way.