Long ago, before the dismemberment of Ymir and the creation of Midgard and Asgard, the underworld was named Jormungrund. It was populated by the dead souls of Jotnar, and some live ones as well - Jotnar are particularly good at traveling to the Deathlands. As far as we can tell, it was looked after by a goddess named Hel, but she was not the Hel who lives there today. Both the name and the job title seem to be something that is passed on. Apparently someone needs to take on the important (and fairly powerful) job of looking after the Dead, and someone is chosen from one of the races when the last Hel retires.

Jotun legend has it that when the old Hel died, the Dead roamed the Nine Worlds for seven years, as there was no one to keep them in check. Every race hoped to have one of its members chosen for this crucial task, which would create an unlimited power-base for whoever was allied with Death, if Death could be persuaded to side with its native race. Mimir, the consort of the last Hel, did what he could to hold things together while everyone waited. Collective breaths were held across the Nine Worlds ... and then Angrboda, the Hagia of the Iron Wood, had a daughter by her consort, the infamous Loki. When the girl-etin was barely walking, it is said, she took on her shapeshifting form, and it was that of a rotting corpse. This was the signal that she was the inheritor of the name and the title, and she was immediately named Hel, or Hela in the Jotun-tongue (the Alfar call her Leikin), and raised to claim the rulership of the Land of the Dead.

Various rumors went around that Loki and Angrboda had done dark magic to make sure that their child would be the Death Goddess; other rumors said that they had merely foreseen that it would be so, and married in order to bring it about. Whether it came about by chance or planning, it was a great disappointment to the other races, who had hoped to pull the Deathlands out of the control of Jotun hands. Odin promptly put a "banishing-spell" on the tiny Hela, which basically banned her from ever entering Asgard, and indeed she has never set foot there.

When Hela came of age, she took over Jormundgrund and entirely recreated it, renaming it Helheim. Mimir handed the care of the place to her and left, going to Asgard to live with the Aesir who had promised him an honored place for his wisdom. Instead of caves and dankness, she opened it to the black sky and planted orchards, and grass grew over the stony burial mounds. She built the castle Elvidnir and swore that no matter how many the Dead, she would find a way to feed them all, if only sparingly. She redesigned Helheim in such a way as to bring maximum peacefulness to those who reside in it; instead of dank caves, it is a subtly ever-changing tapestry of hills and fields and colorful autumn woods.