Faith based classes may, by conduct or specific deeds contrary to their Faith or "Code", be subject to a "fall from grace". This is meant to encourage proper roleplaying of these classes and add to the sense of a "divine hand" granting the class it's powers.
In this event, your stats that grant your defining abilities such as spellcasting or supernatural powers will be adjusted so that you lose the use or benefit of those powers. In all (or nearly all) cases you should be able to atone or repent and regain your full powers.
Examples:
-A paladin who falls from grace could have his Wisdom and Charisma lowered to 10, effectively nullifying his paladin abilities until such time as he redeems himself.
-A cleric who loses the favour of his diety may have his Wisdom lowered to 10, thus losing his ability to cast divine spells until he atones to his god.
In all cases this will be handled by direct DM intervention/interaction. The process is not scripted or automated.
Multiclassing Ramifications
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Losing faith/favour may carry repercussions on your other classes if you have any, despite those class abilities not being faith based at all. This is not intended but is an unavoidable problem.
It is recommended that you avoid mixing faith based classes with other classes who's primary attributes match the faith class'. If you choose to multiclass in this manner regardless of this notice, be aware that this could occur. If the character is properly roleplayed the issue should never arise anyways.
Examples of class mixes affected:
-Paladin/Sorcerer or Paladin/Bard or Paladin/Monk
-Cleric/Monk or Druid/Monk
-Ranger/Monk
In nearly all cases it is combinations restricted in some fashion in the core 3e rules (and also in the FR setting to a lesser degree), but made possible by the loosened multiclassing rules in NWN.
Rule borrowed from the original Daggerdale site.
-credit dolynick-