The treatise tries to examine the phenomenon of totalitarian evil as it was put in the effect within the zone of the concentration camps. The starting point for this consideration forms the literary work by Boris Pahor, characterized by very own experience of violence and totalitarian in the concentration camp of Natzweiler-Struthof. As a key problem appears the testimony of this experience, which includes the philosophical question of what it means existentially to "be a witness". The Answer to this question is developed by reading the key theorists of totalitarianism such as Hannah Arendt and Giorgio Agamben. In the methodological aspect we are relying, as the philosophers mentioned, on an existential hermeneutics, that Heidegger develop in Being and Time and some other representatives of this philosophical orientation. The central finding of this philosophical analyses is that dehumanization as follows from the totalitarian violence is not unique, but it is very factual situation of "witnesses", which itself caught between aspects of the "being witness" and testimony.