Scholars are increasingly taking note of a species of government institutions that fall outside the traditional separation of powers and have come to be known as the “fifth branch“: these institutions are created by constitutional design to engage in independent oversight and investigation of the other branches. Using South Africa as a case study of “fifth branch“ institutions, this chapter dives deeply into the South African cases on corruption (such as the Scorpions litigation, set in its political background) before turning to the more general theme of Chapter 9 institutions in South Africa, then surveying the rise of the fifth branch in constitutional systems around the world. The chapter concludes by evaluating both the value and the limits of the “deep dive“ case study approach to understanding topics in constitutional design.