Does anyone remember that one DreamWorks short called "the legend of the boneknapper?" Because I just realized something crazy and (to me) hilarious about it.
Gobber in one of his stories of the boneknapper said that Thor had intervened.
And everyone called him crazy, until the boneknapper appeared.
This implies that Thor AND the Norse gods exist in the httyd universe. And not once have we seen them besides that one moment with Thor in the short.