The gods home, Asgard, had no wall around it to protects the gods against their enemies. This fact troubled the gods greatly, so when a strange horseman came to Asgrad offering to build a great wall the gods were pleased.
"This will be a great wall" said the stranger, "a true monument to your greatness. In eighteen months from now it will be complete and all your worries will be for naught."
"What is your price Horseman?" asked Odin the All-Father.
"I will accept nothing less than the beautiful goddess Freyja as my wife," replied the stranger, "As well as the sun and moon."
Naturally the gods were furious at the strangers impertinence, to think they would barter of Freyja for mere building work, let alone the sun and moon. By this time Freyja was weeping tears of gold.
However Loki, also known as Loki the Trickster, had an idea.
He turned to the stranger and said: "If you are able to complete the wall in six months you have a bargain." The stranger considered his options, once more looking upon the beautiful Freyja, gold tears making shinning trails down her cheeks and said,
" I'll agree only if my horse is allowed to help me."
The gods looked at Loki in astonishment, 'What were you thinking?' they asked.
"Have no fear," said Loki grinning," In six months he will only be able to build half a wall, the bargain will be incomplete, and we will have half a wall for free."
The gods applauded Loki's cunning and all were pleased.
However, the stranger worked long and hard during the winter, striving to complete the great wall on time, with the help of his horse he managed to quarry the stone for a massive wall around Asgard.
As summer approached disaster stared the gods in the face for the stranger, against all odds, had almost completed the wall.
Odin the All-Father turned to Loki, "Do something Loki," he said, "We cannot allow our Freyja to marry this man, he must be a giant in disguise, and if we give up the sun and moon life will be scarcely worth living. You got us into this mess Trickster, so you must get us out!"
Loki thought for awhile and finally he had an answer, "Without his horse he won't be able to haul the stones to complete the wall."
Loki was a god who was able to change his shape, so that night he transformed himself into a beautiful mare and lured away the stranger's horse. When the stranger realized what had happened he became enraged and his disguise fell away. The stranger was a giant, one of the gods foe's. The gods called on Thor, the god of thunder and lightning. With his mighty hammer, Miollnir, Thor struck the giant with a thunderclap on his head.
That is the end of the story about the giant, but not the end of Loki's.
When Loki thought it was safe to return he was leading a strange eight legged horse called Sleipnir. Loki gave Sleipnir to Odin and said: "Sleipnir is unlike any other horse for he is my offspring. No horse will be able to keep pace with Sleipnir. He will bear you over the sea and through air, and to the land of the dead and back."
As was promised Sleipnir never failed his new master Odin, but not all of Loki's offspring were like him.
One would have to know that Loki was half giant himself, to understand why he had three children by a giantess. The first child is the Fenrir, it is ordained that at the end of the world he will devour Odin. The second child is the Midgard serpent, and the third is none other than the mistress of death herself - Hel.
When Odin came to realize that these children were loose in the world, he had them brought to him. Odin had the Midgard serpant thrown into the sea, but the serpent was so vast that it encircled the world and bit it's own tail. Odin banished Hel to Niflheim, the Land of the Dead, and gave her power over all those who die of illness and old-age.
Even though Odin the All-Fathner had managed two of Loki's children Fenrir was not so easily undone. Only the god Tyr was brave enough to feed this monstrosity, but even he could see that when Fenrir was fullt grown it would do terrible harm. The gods decided to create a strong chain that could not be broken and tie Fenrir up. With one mighty kick Fenrir broke it's bonds and was free. Finally Odin swallowed his pride and asked the dwarfs for help, they agreed and mad a fetter called Gleipnir. Gleipnir was silky and soft to the touch, Gleipnir was made of special ingredients: the soundlessness of a cat's footfall, a woman's beard, the roots of a mountain, the sinews of a bear, a fishes breath and the spittle of a bird. The gods took Fenrir to a lonely isolated island and challenged it to break Gleipnir. Fenrir sensed a trap, so the wolf agreed only if one of the gods was brave enough to place his hand in his mouth, as a token of good faith. Tyr was the only god brave enough and so he thrust his hand into Fenrir's fearsome jaws. So the gods bound the giant wolf with the silken fetter, and when he kicked it only tightened. Enraged by it's captivity Fenrir clamped it's jaws shut and bit off the god Tyr's right hand. Even though the gods knew that it was ordained that a time would come when Fenrir would break free and bring with it death and destruction for all, the gods refused to kill it. The gods said : "What must be, will be."