“ If you want to add a 'supernatural' touch to your campaign, define the rules of magic and the universe. Make your players comfortable with those rules. Then your new supernatural creatures must then break those rules.”
“ The creation of intelligent magical weapons is not an exact science and there are occasional failures, as such think of causing a little more stress to your players by 'rewarding' them with an insane magical weapon
eg:
Agrophobic, refuses to come out of the scabbard without a strength check to draw it.
Haemaphobic: afraid of blood, fight at a penalty against any blooded creatures but really good against undead, elementals etc
Schizophrenic, not just one mind in your sword, lets have half a dozen minds in there, all different and bound to cause confusion
the possibilities are endless”