Loki is a jötunn by birth, son of Fárbauti and Laufey, yet he lives among the Æsir as Odin’s blood-brother and one of their most useful, and dangerous, companions. Clever, shape-shifting, and amoral rather than simply evil, he solves the gods’ problems as often as he causes them — he once turned himself into a mare to lure away a giant’s stallion, and gave birth, in that shape, to Odin’s horse Sleipnir. But his mischief curdles: disguised, he tricks the blind god Höðr into killing Baldr with a dart of mistletoe, the one thing in creation sworn not to harm him.
For this the gods bind Loki to a rock with the entrails of his own son, and set a serpent above him to drip venom on his face; his wife Sigyn catches what she can in a bowl, and when she empties it, Loki’s writhing shakes the earth. With the giantess Angrboða he had already fathered three monsters — the wolf Fenrir, the serpent Jörmungandr, and Hel — who will each play their part in the world’s ending.
Loki á orrostu við Heimdall, ok verðr hvárr annars bani
“Loki shall have battle with Heimdallr, and each be the slayer of the other.” — Gylfaginning 51, tr. Brodeur
At Ragnarök he breaks free, captains a ship of the dead, and meets Heimdall in the mutual killing long foretold.
