The aim of this paper is to determine the conceptual system of the Silesian mythological beliefs that is reflected in the names of demonic figures. These names are not only typical for the region of Silesia but they often refer to other parts of Poland (close or further to/from Silesia). The paper deals with the names of the figures and with their meanings. These meanings are the starting point to determine the features which are helpful for describing figures (and the set of their characteristic features) and for the presentation of the whole conceptual system. The fundamental elements of this system are the four basic categories – spatial locations, outward appearance, functional features (typical actions and roles) and harmfulness/harmlessness to a man. All the features of the demonic figures are presented here according to the levels being the manifestations and projections of these four basic categories.