Today, we have a request for a mythological lady from the far northern reaches of North America: Sedna, the Inuit goddess of the sea and mother of all sea creatures. We're going to call her Sedna today because, thanks to early English- and French-speaking ethnographers, that's the name that most non-Inuit people know her by, but really she's only known by that name (which means approximately "the one down there") to a small number of Inuit peoples around the Baffin Island area. She's more commonly known across Canada and the arctic as Nuliajuk or variations on that name, as well as a slew of others with various meanings from "the sexually voracious one" to "the protector of the sea" to "the terrible old woman." Many scholars simply refer to her as the Sea Spirit or Sea Woman, since like other Inuit deities she is mostly considered the active soul of the ocean itself, and therefore appears most importantly as a representative of the natural powers of the sea and its inhabitants.
Pretty much the only major things that all of Inuit myth agree on are that Sedna is a dangerous and terrifying power in the oceans, and that she must be respected and placated at all costs. Her story is actually a very tragic one, but if you were ever looking for a deity who can take a tragic backstory and leverage it into iron control of her area of influence, Sedna is your lady. The two marriage tales below are sometimes told as a single story, with one following the other, while among other Inuit peoples elements of both are combined into one story, or only one or the other is given as the reason for Sedna's descent into the seas.
There are several variations on the tale, but essentially Sedna was once an incredibly beautiful woman, one who was highly sought-after as a wife by all the local young men. Her father - in many Inuit cultures, Anguta, who later became one of the underworld gods - is all about marrying her off since that would mean he no longer has to feed her, which is a big deal when you live in the Arctic circle and have to hope you can catch enough food to make it through each winter without resorting to cannibalism, but Sedna deems none of her suitors worthy of her and refuses to take any of them. Frustrated by her refusal, which most stories portray as being born of excessive pride, Anguta swears to her that if she won't take a human husband he's going to marry her off to a dog.
If there is one thing Sedna does not tolerate in her myths, it's anyone trying to bully her or tell her what to do, so she calls his bluff and continues to refuse to marry anyone. However, a dog has overheard her father's proclamation, and goes to a shaman to obtain a dogskin amulet, which he is able to wear to take on human form. He then shows up at Anguta's house and presents himself as her rightful husband, and Anguta, delighted to be able to piss off his daughter this thoroughly, agrees and sends her off with the dog (sometimes referred to as Qimmiuk, just meaning "dog" or "dog person") to go live. Depending on the version of the myth, sometimes Anguta just summarily marries Sedna to the family dog without the benefit of humanizing magic, which is most likely intended to knock her pride down a peg by subjecting her to sex with an animal, or sometimes the dog kidnaps her in the night and everyone just sort of has to deal with the situation because of Anguta's hasty promises.
Sedna and Qimmiuk move to a small nearby island to live, but Anguta is dissatisfied; because Qimmiuk is not really a person but a dog, he can't hunt like a human and therefore Anguta is still obliged to feed them both. Every day Qimmiuk swims to the shore and collects meat from Anguta's hunts to bring back home to Sedna, until one day Anguta decides he isn't down for the arrangement anymore and weights his canine son-in-law down with stones, which causes him to drown on the swim back home. Sedna, now widowed, is forced to go back to living with her father, now with entirely new reasons to dislike him. In many versions of Sedna stories, her children with Qimmiuk play important roles in later myths; in some, she gives birth to the first of the amarok, monstrous dog-person or wolf-person hybrids that hunt humans and can sometimes take on human shape, and in others, she gives birth to two litters of children, one of humans, who become the ancestors of the Inuit, and one of dog-people, who are sent away into the oceans on a raft and presumed to become the ancestors of all other peoples.
Either way, Sedna and Anguta are cohabiting again, and for obvious reasons neither is very fond of the other. Sedna is still very beautiful and has many suitors, but she continues to reject them until a particularly handsome man appears, in some versions of the story calling himself Mallemak (meaning "fulmar" or "sea bird"). Sedna is charmed by his attractive appearance as well as the many promises of wealth, comfort and wondrous gifts he has in store for her, so she agrees to marry him, and the two go off to live in his home. However, Sedna realizes in very short order that her husband is prone to disappearing for long periods of time and that he only ever gives her fish to eat, and eventually figures out (sometimes because she pierces an illusion or spell laid over her) that she has again been tricked into marrying a non-human being, this time a sea bird that has been keeping her in his cliffside roost and feeding her fish he catches.
Sedna may not be all that close with her father, but she's not about to be forced to live with a bird forever, so she sends out an alarm to Anguta to alert him to the situation and come rescue her. Anguta does arrive, but as the two of them are fleeing in his kayak, Mallemak returns and is infuriated by Sedna's defection (or in some versions he thinks Anguta is kidnapping her or withdrawing his agreement to let her marry, and let's be honest, that's not unreasonable given Anguta's track record). The bird causes a great storm at sea in his wrath to force them to have to turn the kayak around or risk death on the waters.
Neither Sedna nor Anguta is willing to go back - Sedna because she doesn't want to be trapped there, Anguta because he is afraid of the consequences - so Anguta makes his final move in his bid to win the Bad Parenting Olympics and throws his daughter overboard, hoping that Mallemak will stop chasing him if he no longer has her. Sedna clings to the side of the kayak, refusing to let go and attempting to climb back in, so Anguta finally uses a knife to cut her fingers off, knuckle by knuckle, until she has none left and is left to sink into the depths of the sea.
It is at this point that Sedna becomes the Sea Mother, the undisputed mistress of the oceans to whom all seaside hunters must pay homage and who controls everything that happens the moment anyone steps offshore. Her severed fingers and joints become the first sea creatures, turning into whales, walruses and seals, all of which belong to her forevermore afterward, and she sinks to the very bottom of the ocean, where she becomes its ruler and the ruler of all dark and terrible places, including for many Inuit peoples the underworld of Adlivun, where the dead are sunk in her frozen and watery halls forever without the intervention of other gods.
Anguta does make it back to shore without dying in the storm, sometimes because Mallemak breaks off his attack once Sedna is gone and sometimes just because he was correct in thinking he could kayak away more successfully with only one person, but either way, he does not escape justice. When he reaches the shore, Sedna's dogs (or occasionally Qimmiuk himself, who guards the entrance to Sedna's underworld home and acts as her ghostly representative) attack and savage him, gnawing off his hands and feet, after which Sedna herself calls upon the ocean to reach out its waves and swallow him up, dragging him down to live in her domain forever. Anguta becomes a sort of adjunct to Sedna's power over the underworld, and sometimes carries the souls of the dead from the world of the living to be brought to her, often while punishing them for their transgressions or in some Inuit tales simply torturing them because it entertains him.
While the stories of what happened to Sedna that placed her in the lightless reaches of the sea's bottom are tragic, her resulting control over the ocean, all its creatures and the fates of anyone who ventures out onto it is absolute. Inuit hunters must pray to Sedna for her permission to hunt sea creatures, and hope that she not only allows this but also allows the sea creatures to be weak enough to be captured, something that is very important to making sure that it's the hunter who kills the walrus and not the other way around. Sedna also controls all weather on the sea, making her able to inflict killing storms and blizzards over the waters at a moment's notice if she is displeased, and for many Inuit peoples it was one of the shaman's traditional duties to continually attempt to keep her placated, pleased or at least not actively irritated to prevent such calamities from occurring. One of the ways of doing this is to perform rituals in which Sedna's hair is symbolically brushed, or in which a shaman travels spiritually to the underworld in order to comb out her hair; after eons of time spent alone in the ocean, Sedna has hair so long that it can (and does, if she's angry) literally reach up to the very surface to tangle boats and drag them to the bottom, and without fingers she can't comb it herself and is therefore sometimes calmed or pleased when polite people come and do it for her.
Sedna has a lot in common with other underworld queens like Hel or Persephone in that she ended up reigning over the dead because of the actions of others rather than her own preferences, but also like them, she has become an authority absolute over her domain and a power that must be feared and respected lest it utterly destroy anyone who approaches it without due caution. In spite of the injustices and indignities she suffered in her youth, Sedna has become one of the most centrally important figures in all of Inuit myth, called upon and propitiated almost universally by all coastal Inuit peoples and regarded, along with the earth mother Nunam, as one of the two great sources of life and controllers of the world in existence.
And she has no interest whatsoever in tolerating insolence, misbehavior or disrespect on her seas or toward the sea creatures who are her children. Heroes may be able to venture onto Sedna's cold oceans with her permission, but if they lose her favor along the way, it's likely that they may never return to dry land.