In Norse mythology, Niflheim is the realm associated with primordial mist and cold.
The name Niflheim is commonly translated as “World of Mist” or “Home of Mist.” It is presented as a dark, cold region associated with ice, fog, and the northern cosmic landscape. In accounts of creation, the meeting between the cold of Niflheim and the heat of Muspelheim helps produce the conditions from which the earliest giant, Ymir, emerges.
Niflheim is not simply another name for Hel. Hel is both the ruler of the dead and, in many retellings, the realm where she receives people who die in ways other than battle. Some medieval source passages connect Hel’s domain with Niflheim, but the terms are not identical in every description.
Niflheim is also different from Muspelheim, the fiery realm associated with Surtr. The contrast between frozen mist and consuming fire is central to the mythic picture of the cosmos before its ordered worlds develop.