Ragnarök

 is a malevolent spirit from Grognak the Barbarian's universe, capable of possessing the mind and body of a person. In the issue it appears in, it has possessed Grognak, starting the Grog-Na-Rök, and laying waste to most of the Unstoppables, with the Mistress of Mystery the last woman standing.

Appearances
 appear in the Fallout universe in an issue of The Unstoppables in Fallout 4 and Fallout 76.