For many years, Umbanda has been described as the most characteristic Afro-Brazilian religion and explained by the way it relates to and reflects the broader Brazilian socio-cultural context. In the last few decades though, Umbanda lives an increasing transnational growth, gaining independence from the national context that was once mobilized to explain its appeal. This is the case at “Casa Saint Michael—Haus des Reinen Wassers”, an Umbanda religious community based since 2006 in Cologne, Germany. In this paper, I use the concepts of atmosphere, intercorporeality and interaffectivity to produce an understanding of how spiritual agency is made authoritative in Umbanda rituals called giras. In dialogue with the overall discussion advanced in this volume, I argue that intercorporeal and interaffective dynamics fomented by Umbanda ritual’s atmosphere are the ground for Umbanda mediumship to scale up from a culturally specific religion to a potentially universal form of mediumistic practice.