Hel is the daughter of Loki and the witch Angrboda.
The grave is horrible to every knight,when the corpse quickly begins to cool and is laid in the bosom of the dark earth. Prosperity declines, happiness passes away and covenants are broken. - Anglo-Saxon runic poem, 9th century.
When young,she and her siblings (Fenrir and Jormungamend) were each "put somewhere relatively safe." Hel's safe place was Niflheim (fog-world) where she rules over the dead. But she feels that she was tricked by the Æsir. She was told that she would be a queen, then given the gloomy, unchanging Niflheim.
Part of Hel, being dead, is unable to break promises and is inexhaustibly patient. But the living part longs for life, for the sun, and for Balder the Fair. This is an important aspect of her personality because in herself she istwo contradictory people.
Stanza 31 of the Grímnismál (a 13th century Icelandic poem) mentions Niflheim's position under one of the three roots of the Yggdrasil. There Hel has a massive hall called Eljudnir (rain-damp). In the book it is described as a boundlessly massive palace of alabaster, ivory and glass.
Hel rules over the land of the dead that carries her name. In the first book she manages to bring her love back to life but in life he rejects her.