This article analyses the Korean Netflix documentary series In the Name of God: A Holy Betrayal (2023) and its sequel I Am a Survivor (2025) as sites where religious authority, heresy, trauma, and victimhood are publicly renegotiated in contemporary South Korea. Focusing on the case of the Christian Gospel Mission (JMS) led by Jeong Myeong-seok whose seventeen-year prison sentence was confirmed by the South Korean Supreme Court in January 2025, this article argues that the two series enact what it terms mediatised religious unmasking: a documentary mode that performs explicitly theological functions, asking questions of legitimate authority, naming heresy, legitimating survivor testimony, and relocating sacred agency from the charismatic leader to the victim and witness. Drawing on the theoretical framework of digital religious authority, this article situates the series within the broader transformation of religious authority in the digital age whilst attending to the distinctive institutional and regulatory context of South Korean OTT documentary production. Close attention is paid to the formal and aesthetic dimensions of the two series. The article concludes that OTT documentary now functions as a critical domain for the public negotiation of religious authority, posing new challenges for religion-media studies and for the study of new religious movements.