Loki or Loke is a god or giant in Norse mythology. The 13th century Icelandic Poetic Edda and Prose Edda, two of the very few sources of information regarding the figure, inconsistently place him among the Æsir, as his blood-brotherhood makes him a member of Odin's family. Although Loki is frequently mentioned in 13th century Icelandic sources, scholars generally believe that it is unlikely that he was ever worshipped. Loki is depicted in both the Poetic Edda and Prose Edda as the husband of the goddess Sigyn.
In the Eddas, Loki is described as a son of Fárbauti and in the Prose Edda as also a son of Laufey. Loki also had two brothers (Helbindi & Byleist) of whom nothing is known. Loki is introduced in the Prose Edda as the "contriver of all fraud". Tales regarding Loki in these sources often feature Loki mixing freely with the gods for a long time, even becoming Odin's blood brother before arranging the accidental murder of Baldr by Höðr in the Prose Edda book Gylfaginning. After Baldr's death, the Æsir restrain Loki with the entrails of his son Narfi. He is eventually freed and fights alongside the Jotun against the forces of the Æsir at Ragnarök.
Most information regarding Loki that we have today has been extracted from two Icelandic sources dating from after their Christianization: the Prose Edda, written in the 13th century by Snorri Sturluson and the Poetic Edda, compiled in the 13th century from earlier sources.
Loki is an adept shape-shifter, with the ability to change both form (examples include transmogrification to a salmon, horse etc.) and sex (he turned into a woman to trick Frigg to learn Baldr's weakness). But he had to borrow Freyja's cloak whenever he wanted to change into bird form.
In the Eddic depictions Loki mainly plays the role of a villain: a coward (when he was captured by a giant, he begged for his life and promised to give him the goddess Idun), liar (in Lokasenna, all gods called him a liar), cheater (he tricked Idun into being captured by the giant and only went to save her when threatened by the gods), thief (he stole Sif's hair and stole various things from the giants; he also stole Freyja's necklace and got beaten by Heimdall who was sent by Freyja to get the necklace back), and as a murderer (he killed the god Baldur by tricking his blind brother Höðr into using a projectile made of mistletoe). In Lokasenna, Odin relates what seems to be a lost story about how Loki spent eight years milking a cow like a maid.
Relationships with giantesses is nothing unusual for gods in Norse mythology; Odin, Thor, Njörðr, Freyr are good examples; and since Loki was actually a giant himself, there is nothing unusual about this activity. Together with Angrboda, he had three children:
Loki also married a goddess named Sigyn who bore him two sons: Narfi and Vali. (This Vali is not to be confused with Odin's son with the giantess Rind and sometimes his name is Nari). To punish Loki for his part in Baldr's death, Odin turned Vali into a rabid wolf who proceeded to tear Narfi's throat out. Narfi's entrails were used to chain Loki to a large rock until Ragnarok.
While he was in the form of a mare Loki mated with the stallion Svadilfari and gave birth to Sleipnir, the eight-legged steed of Odin. One story in Hyndluljóð states that Loki ate the heart of a woman and proceeded to give birth to a monster whose name is not given.
In another myth, after Thor threatened to crush all his bones for cutting off Sif's hair, Loki pits the dwarves against each other in a gifting contest. The dwarves make Odin's spear, Freyr's ship and Sif's new hair. He even rescues Iðunn after he gave her to a giant, but only after being cornered and threatened with death by the gods. Finally, in Þrymskviða, Loki manages, with Thor dressed as a bride at his side, to retrieve Mjolnir after the giant Þrymr secretly steals it, in order to ask for Freyja as a bride in exchange. Though, when the guests of the wedding come, Loki shape-shifts into a hawk and leaves Thor to fight them alone.
Even though Loki may have been a liability to gods (leading to the death of Baldr, the birth of Fenrir and other monsters that would eventually engulf the world), his pranks ultimately provided the gods with all their most precious items, from Thor's hammer to the flying ships.
Loki, in the shape of a witch named Þökk with stained black teeth, was the only being that refused to weep for Baldr, preventing the defunct god's return from Hel. After refusing to weep for Baldr, Loki (in the form of Þökk) stepped into a cave, and immediately thereafter changed shape into a raven.
The murder of Baldr was not left unpunished, and eventually the gods tracked down Loki, who was hiding in a pool at the base of Franang's Falls in the shape of a salmon. There they caught Loki with a fishing net. They also hunted down Loki's two children with Sigyn, Narfi and Váli (not to be confused with Váli, the son of Odin and Rind). They changed Váli into a wolf, and he then turned against his brother and killed him. They used Narfi's entrails to bind Loki to three slabs of stone, and Skaði placed a snake above his head so that its venom would pour onto him. Sigyn sits beside him and collects the venom in a wooden bowl, but she has to empty the bowl when it fills up, during which time the searing venom drips onto Loki's face. The pain is then so terrible that he writhes, making the earth shake.
Baldr's murder was also one of the events that precipitated Ragnarök. Loki would stay bound until then. When Ragnarök finally comes and Loki is freed by the trembling earth, he will sail to Vigrid from the north on a ship that also bears Hel and all those from her realm. Once on the battlefield, he will meet Heimdall. They will fight and though Heimdall is ultimately victorious, Heimdall later dies of his wounds.'''
The couple then pray to Hœnir, who hides the son in the neck-feathers of a swan, but again the thurs finds him. On the third day, they pray to Loki, who hides the son amidst the eggs of a flounder. The thurs finds the flounder, but Loki instructs the boy to run into a boathouse. The giant gets his head caught and Loki kills him by chopping off his leg and inserting a stick and a stone in the leg stump to prevent the thurs from regenerating. He takes the boy home, and the farmer and his wife embrace both of them.
Two known depictions of Loki have survived into modern times.
On a spring day in 1950, a semi-circular flat hearth stone bearing a depiction of Loki was discovered on a beach near Snaptun, Denmark. Made of soap stone, the depiction was carved around the year 1000 AD. The depiction features a curled mustache. The figure is identified as Loki due to the seemingly scarred lips, a reference to a story recorded in Skáldskaparmál. The stone is on display at the Moesgaard Museum near Aarhus, Denmark and there is a copy at the Aarhus city Viking Museum.