Thor's Hammer is an expansion by Zarista Games. It's intended for low level characters.

Through the winter, Thor's Hammer reverberated in the heavens, bringing thunder, lightning, even dragons. Omens of evil were clear. By summer, fierce marauders from the North came in their longboats. Theft and destruction became the norm. They looted Holy Island's abbey. No one has dared resist them. They and everyone seem under a curse.