Loki and Sigyn, whose wild behavior shocks contemporary readers, are excellent examples of the depiction of gods in Norse mythology.
Their tragic and intertwined fates constitute a fascinating story.
Sigyn was Loki’s devoted wife, and little is known about her or their relationship.
We know she takes care of Loki after he suffers punishment from the other gods, a role that portrays her as a steadfast wife dedicated to her husband for all eternity.
This article describes the events that led to Loki’s punishment and Sigyn’s response to her husband’s predicament.
It also provides background for Loki’s behavior by explaining his role in Norse mythology.
Also, see Is Odin a Good God? to learn more.
Sigyn, Loki’s Loyal Wife
Loki and Sigyn are both Æsir gods of the Norse pantheon. They were married to each other and had two children – Narfi and Váli. 
Little else is known about Sigyn besides her relationship with Loki, and there are no references to her domain or familial antecedents.
Regardless of such infidelities, Sigyn is portrayed as a dedicated wife.
When the gods punish Loki with eternal imprisonment, she continues to stand by him and serves him selflessly through his torments. 
Loki, the Trickster God
For a god, Loki is a highly ambiguous character. His father, Farbauti, was a giant, and it’s not clear what his mother was. And while Loki is an Æsir god, his status seems nominal.
Stranger still is his role in Norse mythology, where he is depicted as a gleefully malicious agent of chaos who is only concerned with saving his skin.
In tale after tale, Loki uses his ability to change shape to create trouble for the gods, often with devastating consequences. 
For the long-suffering Norse gods, Loki’s role in the death of the beloved god Baldur is one outrage too far on the already expansive rap sheet of a recalcitrant repeat offender.
Exhausted, they banish him to perpetual suffering.
It is important to emphasize that Loki is usually characterized as anarchic and sometimes even nihilistic, but not evil, which is in line with the Norse dualistic worldview of order and chaos.
Chaos was not necessarily evil, and as an agent of Chaos, Loki is different from the Christian devil.
Why the Gods Punished Loki
Baldur – Odin’s son via Frigg – foresaw his death in a dream and her mother, concerned for her son’s life, asked all living things to pledge not to harm him.
All complied, save the humble mistletoe, which nobody thought capable of the feat.
In typical Loki fashion, the trickster god styled a mistletoe-tipped spear, placed it in the hands of Baldur’s blind brother Hodr, and convinced him to hurl it at Baldur, who died and was dispatched to Niflheim.
If that wasn’t bad enough, Loki also thwarted Baldur’s one chance of resurrection.
After the tragedy, the god Hermod convinced the goddess Hel, who ruled Niflheim, to let Baldur go, and she accepted on condition that every living creature mourned the loss.
Unsurprisingly, Loki sabotages Baldur’s chance at resurrection by taking on the form of the giantess Tokk and refusing to weep for Baldur, which leaves him trapped in Niflheim.
How Sigyn Cared for Her Husband During His Hardship
For his role in the Baldur affair, Loki paid a steep price. The gods turned his son Váli into a wolf, which killed Loki’s other son with Sigyn, Narfi.
Finally, the gods bound Loki to a rock with Narfi’s entrails, a fate he would have to suffer until Ragnarok, the end of the world.
To top it all off, the goddess Skaði placed a venomous snake on Loki’s face and tasked it with dripping poison down his throat for eternity, which set the stage for Sigyn’s small but significant intervention.
She took a bowl and collected the snake’s poison to save her husband from its torments.
Unfortunately, every time the bowl filled, she had to empty it, and when she was away, Loki suffered grievously – so much so that the Norse believed his trembling to be the cause of earthquakes.
Despite Loki’s intermittent discomfort, Sigyn’s decision to stick by her man in his hour of need conveyed her loyalty – a virtue the Norse appreciated highly.
The longevity of his sentence only emphasized her faithfulness even in the face of Loki’s many indiscretions and the death of their sons due to his uncalled-for mischiefmaking.
Loki’s Offspring With Other Partners of Various Sexes and Species
There isn’t a label capable of adequately expressing Loki’s vast sexual appetites. As a shapeshifter, he could, and did, change sexes – and species – to produce some of the most terrifying progeny in all of world literature.
Besides Sigyn, Loki also produced three offspring with the giantess Angrboon. These were:
- The goddess Hel. She had dominion over a cold, dark underground realm known as Niflheim, one of the places Norse souls could go after death.
- The giant serpent Jormungandr, who, it was foretold, would emerge from the bottom of the sea to destroy the world at Ragnarok.
- Fenrir the wolf, who was destined to slay Odin at Ragnarok.
Loki also became a mare to mate with the stallion Svaðilfari, giving birth to an eight-legged horse called Sleipnir.
Why We Don’t Know More About Sigyn
Norse culture was passed on by word of mouth through stories, poems, and songs.
Because much of it was not recorded, knowledge of Norse mythology has been derived from texts written long afterward.
Not only is their accuracy uncertain, but they also leave large gaps in explanation and can sometimes be contradictory.
The limited information available on Sigyn comes from the poems Völuspá and Lokasenna in the Poetic Edda and the Gylfaginning and Skáldskaparmál of the Prose Edda, both written in 13th-century Iceland. 
Unfortunately, these only describe her marriage to Loki and the terrible events following Loki’s punishment. , 
While it’s possible that she was a minor deity, it’s also possible that many of her stories died with the Norse.