Saga of Jaraah
The dragonborn are the rarest of the civilized races of Jaraah. The major clans are proud, and fiercely independent. Though they are hosted by human kingdoms, they have a degree of sovereignty and deference not afforded to the regular human nobility. They are allies not vassals. They pay tribute not taxes. They are invited, not summoned. They honor the peace of their hosts, but have their own laws on their estates.
Dragonborn will go to war on the side of their hosts, but will not engage dragonborn in opposing forces. This is not to say dragonborn won’t fight dragonborn, they just won’t do it on behalf of the other races. Should a major dragonborn clan come under existential threat, the others will come to defend it. This hasn’t always been the case, but given the circumstances of the Claacos, the clans came to agreement to aid each other as a warning to those who might think they could eradicate any individual clan.
There are only a handful of major clans. Each has a relatively high purity of a particular dragon ancestor and bears that distinctive coloration. There used to be ten such clans, but not all survived the rise of the Claacos. The major clans consist of 300-500 dragonborn. The lesser clans affiliated with them roughly triple that number, but are not half as large.