This thesis is about encounters, ways of knowing and similarities between Paraguayan, Maskoy people and the anthropologist in Puerto Casado, Paraguay. By discussing these topics, I will explore the borders that mark the relationship between all these subjects, and I will emphasise the mechanisms that can be deployed in order to cross them. I begin by tracing the history of Maskoy people, showing all the encounters and events that have led, in the 1980s, to the legalisation of Territory Riacho Mosquito and to the birth of Maskoy people, as a collective subject and owner of the land. In particular, I describe the events that allowed the creation of Territory Riacho Mosquito from two distinctive points of view: one that of indigenous people, and the other that of the missionaries. By comparing the two perspectives, two different ontologies come to light, and in particular the role of shamans in the fight for land.