By the end of the eigtheenth century the tribal society of Araucanía and the Pampas was shocked by intense actional wars, which immersed its inhabitants in an environment of violence, depredation and death. The civil warfare, a true counterpart of the raids, and frontier trade that characterised Mapuche society during those years, impregnated their daily life, forcing them to remain a state of constant military alert. Historical evidence allows to refer to three types of conflicts: those derived from mutual accusations of sorcery, those that evolved from the ambitions of their leaders to gain power, and those caused by economic clashes between different social segments, Apparently, the traditional systems of mediator and peace-making developed by the mapuche carne to a sudden and costly crisis. Why was there such an epidemic of internal wars events underhed the development of social relationships in Araucanía and the Pampas that obliged to resolve disputes through the use of violence? In what way did these internal breakdowns influence the evolution of the Spanish-Mapuche frontier both in Chile and the River Píate? In this article, we have centered our attention in the Battle of Tromen, an event hither to ignored by fellow historians, which shows the intensity and complexity that acquired tribal conflicts during the second half of the eighteenth century; fought in the trail of Toqui Ayllapangui's rise to tribal power, it constitutes one of the bloodiest confrontations ever recorded in Mapuche History.