9_9 Can't the author keep their mythology consistent?
These are clearly names from old norse mythology, but valkyries are supposed to be some kind of angel equivalent serving Odin, and Gungnir is Odin's spear, so if one is evil, then wouldn't both be?
There is one misconception with your comment, so I'll try to clarify it a bit with what I know: Valkyries are
not "some kind of angel equivalent". They are beings which dictated the outcome of a battle and took the souls of fallen warriors and, from memory, they are more associated with ravens and wolves than doves, raptors or whatsoever. In a way, they are more a "grim reaper equivalent" or psychopomps, and not necessarily in service to Odin. Brynhildr, one of the most famous Valkyries, was cursed by Odin for killing Hjálmgunnarr for example.
The Völsungar saga even implied they may be more human than their pop culture counterpart, with several of them being daughter of kings and giving birth.
Thus, I don't think the opposition Odin vs Valkyries is going against the established mythology. Plus, gods losing their main weapon is a recurrent motif in Norse folklore.