The notion of the Arch-enemy of God and man, of a fallen angel, to
whom power was permitted at certain times for an all-wise purpose by
the Great Ruler of the universe, was as foreign to the heathendom of
our ancestors as his name was outlandish and strange to their tongue.
This notion Christianity brought with it from the East; and though it
is a plant which has struck deep roots, grown distorted and awry, and
borne a bitter crop of superstition, it required all the authority of
the Church to prepare the soil at first for its reception. To the
notion of good necessarily follows that of evil. The Eastern mind,
with its Ormuzd and Ahriman, is full of such dualism, and from that
hour, when a more than mortal eye saw Satan falling like lightning
from heaven [St Luke, x, 18.], the kingdom of darkness, the abode of
Satan and his bad spirits, was established in direct opposition to
the kingdom of the Saviour and his angels. The North had its own
notion on this point. Its mythology was not without its own dark
powers; but though they too were ejected and dispossessed, they,
according to that mythology, had rights of their own. To them
belonged all the universe that had not been seized and reclaimed by
the younger race of Odin and Aesir; and though this upstart dynasty,
as the Frost Giants in Promethean phrase would have called it, well
knew that Hel, one of this giant progeny, was fated to do them all
mischief, and to outlive them, they took her and made her queen of
Niflheim, and mistress over nine worlds. There, in a bitterly cold
place, she received the souls of all who died of sickness or old age;
care was her bed, hunger her dish, starvation her knife. Her walls
were high and strong, and her bolts and bars huge; 'Half blue was her
skin, and half the colour of human flesh. A goddess easy to know, and
in all things very stern and grim.' [Snor. _Edda,_ ch. 34, Engl.
Transl.]