One theme running throughout W is that of Luck. Luck meant something quite different to Vikings, compared to how we lucky modern folks think of that word. Rather than luck being something that is imposed on us by outside forces — getting a lucky break or having a run of bad luck in Vegas — for Vikings, luck was an interior quality possessed by a person, similar to a personality trait or a genetic predisposition. Here is a good research article on the Viking conception of Luck.
The prologue at the beginning (where else?) of W is a short excerpt from Gisli Sursson’s Saga, one of the Icelandic family sagas. The main purpose of this prologue is to introduce the Old Norse concept of “nid” (in English orthography), which is defined as “a form of ridicule whereby a person is represented as worthy of universal contempt.” (We all know people like that, now don’t we?) More specifically, Gisli’s saga provides us with an example of “trenid,” which can be defined as “wood-shame.” Much is left to the imagination in Icelandic saga literature, so I will do likewise.
I have linked to a scholarly paper on “nid” which references Gisli Sursson. This paper may give more information than the average non-Viking needs, but it is interesting nonetheless.