Ragnarök is the name of the event which foretold the end of days in Norse mythology. The events foretold the death of gods including Odin, whose death comes at the hands of the wolf Fenris. The cult known as the Maw of Fenris saw Ragnarök as a plan of attack to wipe out all of humanity, leaving only werewolves to inherit the Earth.
The god Odin would make reference to Ragnarök in 5.19 Hammer of the Gods. As the various pagan gods meet to discuss the coming Judaeo-Christian Apocalypse, Odin reveals he is not concerned, telling the other gods that the end of the world will come when the "Great Serpent Jormungandr rises up," and he is "eaten by a big wolf" (Fenrir). Zao Shen takes umbrage to Odin's claims and the two bicker about their differences in belief.
Ragnarök in Lore
Ragnarök (The Doom of the Gods), in the Norse mythology, is the destruction and recreation of the universe. When the god Baldur was killed by Loki, it set in motion the end times for the gods. Knowing there is no escape from their destiny, the gods prepared for the coming battle the best they could. As they wait, and the "The Great Winter" comes to pass, Loki and his son Fenrir break free of their bindings and would wreak havoc on the cosmos. Giants would lay siege on the gods as Fenrir consumed the skies and the sun. Thor and the sea serpent Jormungand would slay each other, as would Surt and the god Freyr, and Heimdall and Loki. Odin and Tyr would both be eaten by Fenrir, who would in turn be killed by Vidar, Odin’s son. The land would sink back into the seas and reemerge fertile and lush, along with the gods and two humans to repopulate the world.