Ragnarok looms on the horizon of Norse mythology at every turn. The story of Fenrir is not done, even after his chaining. We’ll even set the scene.
Fenrir took the hand of Tyr. Though noble Tyr willingly sacrificed his hand to chain the monster, the gods retreated. Fenrir lashed about trying to break the silken band. The earth did tremble, and the band quivered, but its strength proved the greater. In fear, the gods retreated. There, on the peak, did Fenrir calm himself, hunter’s eyes did narrow on the last of the gods. “Flee from me, Aesir. I will bide your time, and in the end of days will I break my chain and have my revenge.”
We’ll even throw a “To be continued” sign hanging in the air as the scene fades out. Toss in a wolf snarl before the sign disappears, and we’re all good.
So, as said before, Fenrir is a check box for Ragnarok, like many others. Some events, like the Death of Baldur, are very difficult to avoid. How do you actually prevent someone from being killed for all eternity? Others, however, seem more straightforward. Fenrir, for instance, appears to have a straightforward solution. Like everyone who has ever read a Batman comic wonders, why doesn’t someone kill the Joker and be done with him? It’s not like the guy hasn’t earned the death penalty a bazillion times over. The answer for the comic book is simply that he’s a popular villain, and others want to use him in the future. But for Norse mythology, why don’t the gods kill Fenrir?
We know that the gods can and will die, just from the existence of Ragnarok. We have yet to get to it, but Fenrir will also die at Ragnarok, so why not kill him before? We have to bring fate into consideration. The Norse, like many other cultures, believe in fate. The story is written, we have yet to get to the end of it. According to the fated story, Fenrir will die at Ragnarok. It’s not possible for him to die beforehand. Logically, then, any attempt to kill Fenrir, to circumvent the fated prophecy, will bring it about. The time at which Fenrir dies is Ragnarok, no matter what. Killing him will bring Ragnarok early. This is the ultimate trick of prophecy that stymied so many of the Greeks (seriously, never go to Delphi, ask Oedipus).
Odin actually has a unique plan to—sort of—circumvent the prophecy. Instead of cutting things out of the story, he inserts more story into the book. Or, to give it the cultural analogy, instead of cutting Fenrir’s thread out of the tapestry of life, he splices in more tapestry (the Norse, like the Greeks and many others, viewed fate as being spun, woven, and cut as threads in a tapestry).
So Fenrir, like Loki—who was likewise chained up after killing Baldur, is actually protected by prophecy. The gods dare not do anything more than restrain him lest they bring about the destruction they seek to avoid.