This dissertation examines the extent to which decoloniality can be employed as a theological hermeneutic to foster Christian unity and reconciliation. It investigates whether decoloniality can disrupt the settler colonial imaginary that developed from Eurocentrism, white supremacy, patriarchy, and exploitative capitalist practices. Anchored in Reformed theology, this study draws on the theory of coloniality/decoloniality, settler colonial studies, the study of religion, and the theological concentrations of ecclesiology and missiology. It poses three questions: 1.) How is theology implicated in the formation of the settler colonial imaginary in South Africa? 2.) To what extent can decoloniality be applied as a hermeneutic in the Reformed tradition to render white Christians ethically and morally vulnerable to the unifying power of the cross? 3.) Can the decolonial telos of pluriversality be applied theologically to facilitate the church's transformation from functional coexistence to the splendor of a new Ephesian moment?Chapter 1 responds to the call of the fallist movements for decolonization. It confronts the personal, prophetic, and pathological dimensions of post-apartheid society and the consequences of coloniality. Chapter 2 investigates power relations within the settler colonial imaginary and the role Christian evangelism played in its formation. Chapter 3 establishes decoloniality as an essential hermeneutic for understanding the contemporary South African situation. It focuses on Sabelo Ndlovu-Gatsheni's contribution to decolonial discourses. Chapter 4 examines the theological application of decoloniality to South Africa's pressing social challenges in light of the legacies of imperialism, colonialism, and apartheid. The thought of theologians Vuyani Vellem and Gerrie Snyman is explored as it relates to the message of the cross and vulnerability. The dissertation turns in Chapter 5 to the pluriversal telos of decoloniality and the promise it holds for church unification. In light of Christ's prayer "that they may all be one" and the vision for convivial unity across difference in Ephesians, where the metaphors of temple and body are central, decoloniality is found to be an essential hermeneutic for nurturing a new Ephesian moment. However, it is not sufficient. Authentic vulnerability on the part of the white community is necessary to unsettle the settler colonial imaginary.