Hel

Here is my take on Hel (or Hela), the guardian of the world of the non-heroic dead in Norse Mythology ! Her domain, also known as Hel (or Helheim to avoid confusions), is located in Niflheim, a cold and misty world. She's a jötunn, the daughter of Loki and Angrboda, and thus the sister of the giant wolf Fenrir and the giant sea snake Jörmungand. More or less forcefully, Odin appointed her as the ruler of Helheim.
Hel is also known to have one half of her body being dark-skinned, skeletal, or even rotten, the other half having a brighter skin tone, and a beautiful look. She has a ferocious hound named Garm as her pet, and would be the only being able to tame Nidhogg, the giant wyrm that gnaws the roots of Yggdrasil...