Replace Cavemen’s quest artifact with scales from the Chromatic Dragon (their quest then becomes “kill the dragon that is terrorizing our people” instead of “fetch the artifact from the dragon who stole it”). The scales only drop when she is killed, rather than her being generated with them (thus, they can’t be stolen). The scales could either be implemented simply as a base item akin to chromatic scales in UnNetHack which provide a cocktail of resistances, or as an artifact. If implemented as a non-artifact, the Caveman role will have no associated quest artifact.

The scales should NOT be enchantable into scale mail. The pile of resistances is good enough.