Skaa were the peasant class of the Final Empire. According to Ministry doctrine, the skaa were the people who did not support the Lord Ruler in the days before the Ascension. So as a punishment, when the Lord Ruler took the power at the Well of Ascension, he altered the characteristics of the inhabitants of Scadrial, dividing them into two groups- the nobility and the skaa. However, due to a millennium of interbreeding, the differences are mostly erased or nonexistent.