Pestilence and famine.
Hel herself was supposed occasionally to leave her dismal abode to range the earth upon her three-legged white horse, and in times of pestilence or famine she was said to use a rake if a part of the inhabitants escaped, and a broom when whole villages and provinces were depopulated, as was the case during the historical epidemic of the Black Death.
The Northern races further fancied that the spirits of the dead were sometimes allowed to revisit the earth and appear to their relatives, whose sorrow or joy affected them even after death, as is proved by the Danish ballad of Aager and Else, where a dead lover bids his sweetheart smile, so that his coffin may be filled with roses instead of the clotted blood drops produced by her tears.
“‘Listen now, my good Sir Aager!
Dearest bridegroom, all I crave
Is to know how it goes with thee
In that lonely place, the grave?’
“‘Every time that thou rejoicest,
And art happy in thy mind,
Are my lonely grave’s recesses