Helheim

Helheim - the "Norse Underworld" in the game Underworld - is a name given to places previously referred to as "Xibalba" and "Avalon", and the final level of Underworld takes place there. Natla informs Lara about "Helheim" in the Mediterranean level, and that no one can enter "Helheim" without Thor's Hammer. At one point Lara tells Zip; "Helheim, Zip. Various myths use different names, but they all apply to the same remnants of the ancient world". This melds the plots of Legend and Underworld to some extent, but as a statement of mythological lore makes little or no sense.

Helheim in folklore

Hel (lower right) from an 18th century manuscript

Helheim or Helgardh according to the Norse Eddas is actually a palace in Niflheim for the Norse goddess, Hel. [1]. Helheim is also the name of a glacier in Greenland [2].