This article examines the actions of Francisco Mariluán and Venancio Coñuepan, two rival caciques of the Mapuche indigenous people, during Chile’s independence wars to understand how indigenous leaders defended their sovereignty and shaped the transition from colony to nation in Spanish South America. Between 1819 and 1825, lands in southern Chile and western Río de la Plata that were controlled by the Mapuche became the stage for a civil war between Spanish royalists and Chilean patriots known as the guerra a muerte (war to the death). Mariluán and Coñuepan supported different sides in the conflict, but they expressed their support through diplomatic practices rooted in material and ritual reciprocities of negotiation, letter writing, and gift giving. By centering how Mariluán and Coñuepan imposed interethnic ritual negotiations (parlamentos) and diplomatic protocols on Chilean leaders, the article argues for the importance of indigenous practices of reciprocity and definitions of authority on the former frontiers of the Spanish Empire. These reciprocities governed interethnic encounters and changed the character of the conflict into a Mapuche war.