The aim of this paper is to consider the role of the devil in early Christian approaches to evil and suffering, using as a case study theological reflection on this theme by Basil of Caesarea and Gregory of Nazianzus. Through a close reading of three texts concerned with the origins of evil, suffering, and the continued presence of the devil on earth after Christ’s victory, I propose the devil’s existence contributes to the mystery of evil for Basil and Gregory. Put simply, the devil does not serve as a strategy to solve problems of evil and suffering. The devil himself is a problem.