I've kind of got an idea for a character, but I'm not sure if you'd allow it.

Basically, they'd be an average citizen who was taken away by the kobolds, and cursed by one of their shamans to become one of them... they would then leave the cave to an (at best) lukewarm welcome, and would have some motivation to both leave to become an adventurer... and to try to learn the arcane arts, if nothing else, then to try to undo the curse (though, they will never be able to do that).