Hel
Hel is the daughter of Loki. She lives in a palace of mist and darkness which is secured by thick, high walls and strong gates. It is here that she receives the souls of those who died of sickness or old age.
Hel promised to release Baldur if all things would weep for him but Loki ensured that he was unable to leave and he had to stay behind Helgring (the gate of Hel).
Adapted from 'A guide to the Gods' by Richard Carlyon