The thirteen dragonmarked houses collectively wield power on a continental scale; they are arguably the greatest power brokers in Eberron. Membership in a house is hereditary, and each bloodline has a particular mark associated with it. These marks grant their bearers a distinct competitive advantage in certain aspects of trade and commerce. Since the marks first started appearing on the skin of humanoids thousands of years ago, the dragonmarked houses have consolidated their power and built enormous commercial enterprises. They now have near monopolies in key goods and services, and they do not hesitate to crush competitors. Yet they are also patrons of the arts, sponsors of scholarship and exploration, and innovators that have enhanced the lives of nearly all Khorvairians.