A spellcaster is a character capable of casting spells.
Spellcasters in Neverwinter Nights are divided into arcane and divine casters. Arcane caster (bards, sorcerers, and wizards) are considered to cast their spells by tapping into magical forces that permeate reality. Divine casters (clerics, druids, paladins, and rangers) are considered to cast their spells by channeling power from a superior being (a deity or nature itself). This distinction has little effect on gameplay, though. In Neverwinter Nights, arcane casters are subject to arcane spell failure caused by wearing armor or using a shield, whereas divine casters are not. In addition, divine casters know all spells available to the class at a given spell level, while arcane casters are limited to spells chosen when gaining a level and (for wizards only) learned from scrolls.