now I have only done this once, but maybe make your new character his twin. That way you can keep most of the fighting style and have the same background. That or you can make his younger, or older, brother (or sister if you feel so inclined). This also gives you a goo plot hook for your cahracter to raise enough money for a reseruction, or vengance, whatever. Only works once though, remember that. You don't want to have the sixtuplets in your family come one after another after your lost brother and sisters.