This chapter discusses localized religious-modernist developments within the Limbu community in the borderlands of Buddhism in the eastern Indian Himalayas. It examines the invention of Yumaism by focusing on the Limbu middle class' agency in relation to their lived contexts, through an actor-oriented and processual approach. Yumaism draws on elements from indigenous religious traditions, Tibetan Buddhism, Christianity, Hinduism, scholarly and orientalist discourses, and modernism in general. The proponents of Yumaism are similarly attempting to define their religion as such a way of life, a philosophy that is both rational and modern, while at the same time being steeped in the long historical tradition of the Limbus. While the process of modernization involved in the creation of Yumaism and the impact of Buddhism upon this process should not be underestimated, the dynamics of the modernization of the Limbu religion are grounded in local economic changes, politics, and ethnic relations.