Most of this is gone over briefly in chapter one, but i'll go over it again in a little more detail here.
There are three main classes of demons; Higher, Middle and Lower, With varying degrees of power within each class. All demons are named after the animal they most represent, in either personality and/or appearance, for instance there are dog demons and snake demons, however these are broad categorizations, at least for the middle and higher class demons, who are usually referred to in clans. Clans usually consist of family groups and can be traced back many generations. When a demon child is born they already have the brand of the most dominant clan burned into their aura, in the case of two equally powerful clans they will bare the two symbols combined in some way. When looked at with the second sight theses symbols are easily visible. The demon will also have a physical representation somewhere on their body, usually in the form of a birthmark.
Lower class demons are by far the weakest. They are little more than animals and even the strongest could be defeated by a human worrier. Lower class demons are little more than animals, driven by hunger and a need to destroy. They are viewed in detest by other demons and are pests to humanity. They have little inteligence and therefore no aura and no magical skill. However these demons are still dangerous and often plague villages and townships. Lower class demons do not have access to the second sight and do not organize into clans. There appearance is usually a mockery of the animal they are named after and they are not able to change their form.
Middle class demons are considerably more powerful than lower class demons. They are intelligent beings, about on par with humans, and have souls and auras. While they are born with little natural skills in magic, with training they can become quite adept. Unlike lower class demons they do form into clans and, with practice, are able to take on more than one form. The lower middle class demons have strength that is slightly less than the average human. They have souls and therefore free will, so they can become either good or evil. These demons can be strong foes, but usually stick to themselves, as there are not as many of them as lower class demons. Middle class demons are usually only skilled in one branch of magic, and can live for considerably longer than humans.
Higher class demons are the most powerful of all. They have souls, auras and magical powers. Unlike middle and lower class demons, they have no limit to there power and humans are little competition for them. However there are few higher class demons compared to the other types and they do not usually meddle in human affairs. Higher class demons have clans and the ability to choose to be good or evil. They have great magical talent and can become skilled in more then one branch.
Middle class demons, higher class demons and humans are all able to interbreed. In the case of an interbreeding between a demon (of either class) the child will have some of the powers of the demon parent, usualy to a lesser extent, and some of the characteristics of the human parent, however such children are very rarely accepted by either the demon or human societies and are treated as out casts. If the demon blood is diluted by a few generations, humans may accept children relitevly easily, but no matter how little the amount of human blood may be, demons that are part human are almost always veiwed as less by other demons.
The powers of a higher and lower class mixed child depends entierly on their gender. The child will have the same level of power as their parent of the same gender and will be classed as such, so if a male higher class demon and a female middle class demon had a son, the son would have the reletivly the same amount of power as his father and would be classed as a higher class demon, this type of cross breeding is fairly common and is widely accepted among demon society.
That's all i can think of at the moment please tell me what you think