Really quick. SO. A Demon. Is anything born of TWO demon parents. A Cambrion, is anything born of ONE demon parent and something else. Even if the other parent is a Cambrion or a Chaos scarred, the child is a Cambrion if it has ONE demon parent (unless the other parent is an Angel but don't ask). A child is a Chaos scarred if ONE of its parents is a Cambrion OR a Chaos scarred. So you can have Chaos scarred orcs, chaos scarred humans, etc. But you are a Cambrion (its actually a technical race) if you have ONE demonic parent. Same for the other two races like this. Angels, and Devils 

Also. Will is not always directly related to magic ability. Its related to magical POTENTIAL