Unlike Christianity, the only reference to punishment after death in Norse mythology was made by Snorri Sturluson, author of the Younger Eddas. He makes mention of a land called Náströnd which existed adjacent Helheim. In Náströnd, which is reserved only for the most wicked (including oathbreakers), you are perpetually eaten by snakes for all eternity. So remember kids, don't break your oaths!