In every culture there is an isolated world where the souls of the dead are forced to dwell. In Norse mythology, those who die heroically or in battle are taken to Valhalla to prepare for the upcoming battle that would end the world. Those who died as a coward or took their own life were sent to the World of Darkness and Ice. Nifetheim is the prison for these souls and Hel the Goddess of Death, is their warden.
Hel is the daughter of Loki the God of Mischief and her mother