Hel is a Norse goddess. She is the daughter of Loki, and the Giantess, Angrboda. The other two are Fenrir ,and Jormungand(The Midhgard Serpent).Hel didn't have a great life. Being depicted as a woman whose bones were exposed on one half of her body, her appearance disgusted many others, so much so that other Gods wanted nothing to do with her. She was seen as an oddity, a freak, and grotesque. Hel was filled with great lonliness and despair. She then asked Odin if she could leave Asgaard.
Hel was then cast down into the Netherworld and became the ruler of the Underworld. She gave Odin two ravens(Huginn and Muninn) in return for making her ruler of the Netherworld. Hel's name is named after her, Helheim. She determines the fate of those in the afterlife. Helheim also serves as a place where souls can wait to be reincarnated.
Nordic Shamans call upon her for protection and wear a helkappe, which is a mask that makes them invisible so they can slip into the realm of death. In divination her symbol is hail, which is an embodiment of the realm she rules. She is often linked to Isis, Osiris, and Hekate. Hel has been muddled over the years by ignorance as being depicted as an ugly entity waiting to eat children.
SOURCES: Hel: Ruler of Underworld, Guardian of the Undead by Rowen Saille
Hel, Norse Goddes of the Dead by angelfire.com