I've realized that I can write a more complex nonfiction-style setup than I'm comfortable writing as a narrative.
So I'm trying to nail down a simplified approach to the magic and such. I think I've got the Guilds in a pretty good place. As for the Nobles, I'm streamlining that concept to focus on the Dragon-Blooded aspect, since the relationship with Dragons plays a key role and the idea of ability being passed through bloodlines ties nicely to the conceits of the aristocracy.
These empowered individuals are known as the Dragon-Blooded Elemanteros, or the Dragon-Blooded, or simply the Elemanteros [el-eh-mahn-TEHR-os]. Elemantero is singular.
The ranking members of each major Noble House and their scions can control elemental forces because they have been physically imbued with the enchanted blood of their House Dragon. The abilities associated with being one of the Dragon-Blooded can pass down from the originally imbued generation to the next, but this isn't reliable and such traits attenuate after a few generations. What's typical is for a person of the ranking noble line to receive an infusion of Dragon blood during their coming of age initiation rites. This happens for both young men and women. Bastard offspring with elemental powers are possible, but they'll be wild talents unless they get some sort of training.
Being Dragon-Blooded gives you a stronger constitution than mere mortals, giving you a longer natural lifespan and it also gives you access to whatever elemental forces your Dragon sire has mastered. A Dragon that has mastered a wide range of elements can pass along a much greater variety of ability to its House.
The caveat is that while a Dragon might master conflicting forces, you'll only be able to handle one major element and whatever its secondary related elements may be, as per the Elemental Schema chart. The specific Element(s) you can control depends upon your psychological makeup. This also effects how you control those elements. Those who are not suited to the only elements available will end up controlling them reluctantly or doing so in unusual ways.
Repeated infusions of Dragon Blood can increase your power and heal severe injuries, but every time you accept it you are transformed into a more reptilian form. This is called Embracing the Dragon. And you don't ever want to take blood from two different Dragons into your body, even many years apart. Very Bad Things happen.
Being Dragon-Blooded only gives you the power to manipulate certain elements. The skill to do so comes through training, natural aptitude, imagination, and will.
This creates a form of magic that I think has interesting story implications and possibilities.