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There is also a placeholder icon suggesting that the "Weapon Master" was originally "Kensei" - ir_kensei.png - 
and also you can see this with cls_pres_kensei.2da (now unused) which also has the script variable X2_AllowKensei.
Hardcoded Lines
See Hardcoded classes.2da lines. Boy are there are a lot of them.
2da Columns
For more information on the NWN:EE caster spellbooks see Custom Spellbooks using classes.2da and spells.2da
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