Fenrir

The story depicted in the stone walls started with the disaster 'The Ragnarok' that spelled the end of the Asgardians, as the massive wolf Fenrir killed many of the gods including the all-father himself, Odin.

Fenrir's rampage practically destroyed the world and heralded the end of an era. Even when the creature was finally slain under the blade of Vidar, one of the Ashgardian gods, the myriad of gods who died meant that the age of gods had finally ended. After the death of the wolf Fenrir, it was then the birth of the wolf's curse was mentioned. 

The old man started to read the writings on the wall. 

"The Giantess, old and frail, spoke from within the Ironhood. In the east, the brood of Fenrir was born. They shall walk amongst humans, only to shed their guise and show their monster form before devouring the sun."