Niflheim is one of the Nine Realms.
- In the non-canon video game Thor: God of Thunder, Niflheim is a base and thrall world of the Frost Giants. It is home to the Cave of Ages, where Odin imprisoned Mangog. Niflheim is noted for being the location of Hel, a dark region where the inhabitants of the Nine Realms apparently dwell after death.
- In Norse Mythology, Niflheim is the primordial realm of mist, ice, and cold whose rime flows combined with the flames of Muspelheim to form water which the gods used to create all of Midgard.