Quoted from another thread:
I feel that wizards and magic should primarily be a challenge factory. Wizardry and magic could be obtained through a strange mood after a certain population has been reached, or a wizard could arrive much like a noble. They'd then demand certain workshops or similar utilities to be set up where they can experiment and research. The effects of their research would be almost completely arbitrary. You could suddenly find all the bones in your refuse pile animate and terrorize your butchers. Conversely, the wizard would occasionally create magical amulets that could benefit your soldiers, workers, or even nobles. An enchanted amulet given to a soldier could increase the chance of a martial trance occurring. A magical pair of gloves given to your legendary mason could increase the frequency of masterpiece furniture made. The primary function of the wizard, however, should be to create challenges (and, subsequently, fun) for the player to deal with. The wizard would escape prosecution for any crimes he/she commits as long as he didn't directly cause the death of a dwarf. A stray fireball hitting a nearby peasant would result in the wizard being carried off to the gallows while an animated piece of dwarven cheese choking your baron would allow the wizard to remain blameless.
There are a few suggestions here relevant in context: We are discussing the strange moods a wizard could get, however, it might be that someone actually turns wizard from a strange mood, like the alchemist or (runic) engraver.
Also, from this comes the notion of a dwarf having strange moods more than once. It a dwarf turns into an exotic specialist from his mood, or arrives as a specialist immigrant like a noble, (say wizard or flying spaghetti ninja or something) then he could get a second strange mood.