Stefan Müller, social worker and theater pedagogue (UdK), already appeared in the late 90s at Ballhaus Naunynstraße as an actor in the plays Graue Würmer and Am Schwarzen Meer in der Revolte, melancholische Terroristen und ein Marienköfer by Yalçın Baykul. Before and after that he worked in several projects as an actor and theater educator and as a storyteller. At Ballhaus Naunynstraße he performed with Liga der Verdammten.