In the basic book there is a 5 point magic sword that bestows the "Stupidity" special rule on any character or monster that suffers an unsaved wound from it. Correct me if I am wrong but once you are in combat you don’t roll for stupidity; so why would someone take this? I can only think of a couple times where this might be at all useful. 1. Hit a mage with it for the possibility that he/she will not be able to cast spells the next turn. Chances are if the mage is in combat, depending on the mage, he/she will not be around next turn anyway. 2. You suicide a character into something really big in the hopes of doing 1 wound and making it stupid for the rest of the game. Does not seem to be a very efficient use of a hero. 3. You have a 5 point magic sword that can hit ethereal things. Anyone got anything else?
Best use I can think of... some armies have really cheap heroes who are pretty much disposable anyway. Put this weapon on the cheap hero and try to get him to put a wound on a big monster that is running far on the flank, away from general and bsb. Some big monsters have bad Ld, so in the event you can actually put a wound on it and make it stupid, it will be a lot less reliable, possibly winning you the game if it fails a stupidity test on a turn it was supposed to charge. But yeah, a real long shot, that's why it is cheap. I think the skink chief on terradon might be our best bet for using this, maybe you just need a cheap magic weapon to hit ethereal stuff.