Ouroboros Unchained

The end of the world is quite difficult to organize, inexorable though it may be. Humans have gotten pretty good at delaying it. But you can only run so far. With Yggdrasil crumbling, Mjollnir stolen, and Jormungandr betraying his father, Hiccup Haddock II has left his descendant plenty to deal with. But if he can't do it, no one can, partly because there'll be no one left to try.