The idea of reciprocal obligation is central to the Savirai culture's theory of governance. Although the Savirai have a strongly hierarchical hereditary social structure, obligation is not only up the structure, but down it as well. Hence, although warriors are obligated to provide their masters with their arms, and bondservants their service, everyone further up the hierarchy, up to and including the emperor, must satisfy their reciprocal obligations in turn, whether that be the chance for honor for the retainers, peace and protection for their farmers and merchants, or kindness to their servants. In practice this works as a loose judicial system that both upholds and defines the legitimacy of the top echelons of society, who must fulfill their obligations with honor or risk attainder or rebellion. The fulfillment of obligation can also deliver eventual promotion within the hierarchy, and the abandonment of it could likewise lead to demotion.
The idea of reciprocal obligation had long existed before the Savirai kept a written history, with origins in the old Mirairid, but it was codified into law by the chancellor Qamiras of the house of Vatai, approximately a half-century prior to the Nahari conquest and formation of the Dual Empire. When the Dual Empire was formed, these theories of obligation were interpreted to define the vassal-lord relationship in the constituted Nahari Empire as well.
When the Second Aitah created the Emperor Qasaarai IV Her Flamebearer, she invoked a special obligatory contract that extended beyond even the borders of the Dual Empire. The Flamebearer was charged with the obligation to protect all of Her Faithful from the Enemies of the Light, and thus accorded the responsibility of leading her legions into battle.