The DSA - Marbo Vademecum is a comprehensive reference work that delves into the complex world of the role-playing game "The Dark Eye" (DSA). It illuminates the dual nature of the deity Marbo, who is portrayed both as the gentle daughter of Boron and as the ancient vulture mother UmmGhulshach. Readers are introduced to the history and beliefs of the clergy, particularly through the perspectives of the last high priestess Maharaha and the priestess Marbolieb. Maharaha, who lived during the Dark Times, left behind a valuable archive of clay tablets that provide deeper insights into the tenets and history of the temple in Omlad. Marbolieb, on the other hand, faces the challenge of finding her own path to the goddess while grappling with the centuries-old records and the quest of the Marbiden Order. This Vademecum is not only a useful tool for players but also a source for anyone looking to explore the mythological and cultural aspects of Aventuria.