There seems to be no shortage of theories of fiction. From different points of view, a wealth of concepts of fiction has emerged in the course of the past century, making it seem idle to add another specimen to this series. Nevertheless, a theoretical deficit seems to persist in one respect. For the existing approaches largely ignore the differences in the conditions of the constitution of fiction in the various media. Thus, a media-differentiated theory of fiction is missing. If traditional theorising has neglected this aspect, such an omission seems to result from its primary interest in the epistemic status of fictions. Instead, the approach presented here foregrounds an aspect that is already inherent in the concept of fiction itself. The underlying Latin verb “fingere” means ‘to form’ or ‘to shape’. Characteristic of all fiction in artefacts is therefore a “shaping” of reality. Their respective truth value appears as a “consequence” of this shaping. In this respect, fictions of artworks maintain a dominantly operative relationship to reality, to which their epistemic status is subordinate. These general considerations on the theory of fiction will be used in the article presented here to determine the specific status of fiction in two media that, at first glance, owe their existence to very different cultural traditions: traditional theatre and computer simulations, especially computer games. We would like to define their commonality with the theoretically extremely fruitful concept of “réalité virtuelle” borrowed from Antoine Artaud. Its characteristics, however, have to be defined in a different way than Artaud’s for an adequate description of theatre-specific fiction. We define them – taking into account the modalities of the use of the concept of reality itself – as a “spatio-temporal presence of (thinkable) possible reality”. Against the background of this theoretical basis, we will conclude by discussing differences between the various media that can be subsumed under this concept.