Of all the paranormally connoted opponents a hero can face in medieval Icelandic literature, the berserkr is one of the most frequently appearing monstrous antagonists. The chances of encountering one are equally high in the fornaldarsögur and the Íslendingasögur, and beyond these genres they appear in Heimskringla, Snorra Edda and both eddic and skaldic poetry. In addition to these high and late medieval narratives, scholars have found them reflected in diverse sources from antiquity to the Viking Age, ranging from Tacitus’s Germania to Migration Age bracteates and Viking Age rune stones. Drawing on all of these sources, scholars have tried to paint a coherent and cohesive picture of these inconsistently depicted figures, arguing for instance that they reflect remnants of Odinic Männerbünde, or of human-animal shapeshifting. It is this latter concept that this article will focus on, trying to revise some of the assumptions that have been made about berserkir and their relationship to shapeshifting and monstrosity.

One of the problems of previous work on berserkir is that, in many cases, scholars do not adequately differentiate between berserkir appearing in different genres of saga literature. It is, however, important to distinguish between different kinds of berserkir: in the fornaldarsögur, for example, some berserkir can change shape physically, whereas — as I will argue below — this does not happen in the Íslendingasögur.