Social hierarchy is an important theme in the book and closely resembles the Western Medieval model of society. Alethkar is organized along the lines of a feudal state with one king commanding multiple lords who each have their own army and lands and enjoy varying degrees of autonomy. In Western feudal societies, the most important factor in determining social status was lineage, which determined the inheritance of power, wealth, and titles. In Alethkar, Sanderson takes the notion of family lineage and aristocratic bloodlines to an extreme, with genetics playing a major role. People with light eyes are automatically considered of high social status, as this phenotypical trait evokes the glowing eyes of the legendary Knights Radiant. Those with dark eyes are seen as commoners, regardless of how they got their eye color. In such a world, there is almost no possibility of social mobility. The one exception is when a darkeyes wins a Shardblade in battle and his eye color lightens. There is a brief mention of the possibility of a high-ranking darkeyes marrying into a low-ranking lighteyes family, but that does not seem to be a prevalent trend, as the social hierarchy of Alethkar incentivizes aristocratic families to marry and procreate only with similarly light-eyed people to preserve power and status.