Niflheim

"Sunken ship, dragon hunters, the creeps... I bet this thing is crawling with ghosts. And other such spirits planning on dragging us down to the dark Viking underworld where they will torture us by tickling us for eternity!!"

- Tuffnut Thorston

"Niflheim?"

- Ruffnut Thorston in Night of the Hunters, Part 1

Niflheim is the Norse mythological location where unworthy Vikings are sent when they die, and possibly those who didn't die in battle. It's mentioned in the Race to the Edge episode "Night of the Hunters, Part 1".

History
Niflheim (pronounced “NIF-el-hame;”) comes from Old Norse Niflheimr, meaning “World of Fog”. It's one of the Nine Worlds of Norse mythology and is overtaken by primordial darkness, cold, mist, and ice. It is ruled by Loki's daughter Hel.

The word “Niflheim” is often used interchangeably with “Niflhel,” a poetic embellishment of “Hel", the world of the dead. “Niflhel” is found in Old Norse poems.

The well of Hvergelmir, from which all the rivers of earth flow, is said to originate in Niflheim.