This article examines the Nine Emperor Gods Festival as a site of religious transformation among Chinese communities in Southeast Asia, offering a lens through which to theorize how migration, memory, and marginality reshape ritual life. While the festival originated in Qing-era China, it was reconfigured across the nineteenth and twentieth centuries through colonial labor migration, local ritual innovation, and the institutional life of overseas Chinese organizations. Adopting a longue durée perspective, we trace the shifting identities of the Nine Emperors, also known in the diaspora as the Nine Emperor Gods, and their mother, the Dipper Matriarch, alongside the transformation of the festival’s ritual structure. We propose the concept of diasporic religious ecology to theorize how Southeast Asian Chinese communities reconstituted religious authority outside East Asia. These communities invoked China as a cultural origin while simultaneously rejecting its political legitimacy. The Nine Emperor Gods, often recognized as exiles, martyrs, or liminal figures, mediated these tensions: their ritual features became metaphors for the diaspora’s tenuous but enduring relationship with China. By treating the festival not as evidence of survival but as a method of reckoning with displacement, this study positions religious transformation as a medium through which exile, rupture, and authority are not merely remembered but actively reconceptualized.