Akkorokamui

Before anything else: this one is not a yokai, and calling it one gets the story wrong.

The Akkorokamui belongs to the Ainu, the Indigenous people of Hokkaido and the northern islands, whose beliefs are their own tradition and not a branch of Japanese folklore. The word kamuy does not mean "monster." It means something closer to a power — a being with its own will and standing, which may be dangerous, may be owed respect, and is not the same category of thing as a creature in an Edo picture book. What follows is an Ainu story, told as one.

The spider that was moved to the sea

It starts on land, and it starts as a spider.

A vast spider called Yaushikep devastated the village of Rebunge. It was beyond anything the people could handle, so the elders appealed to the gods, and Repun Kamuy, the god of the open sea, intervened — dragging the spider off the land and down into Funka Bay, and transforming it there into an octopus.

It's a transformation with real visual sense to it: all those legs, that low sprawling reach, moved from one element to the other. And what it becomes is enormous. The accounts describe a body covering something like a hectare, a hundred metres across, filling a meaningful fraction of the bay it lives in.

The most striking detail is the color. It is so intensely red that the redness shines up out of the water into the sky above it.

And that turns out to be a mercy. The glow on the clouds is a warning. Sailors who see the sky over the bay turn red know what is underneath them and have time to steer away. A creature that can destroy a boat, announcing itself in advance, every time.

Feared and honored at once

Fishermen in Uchiura Bay carried great hooks in case they met it. But fear was never the whole relationship — the Akkorokamui also drew reverence, and over time was taken up into Shinto practice as a minor deity, given fish offerings and credited with healing: specifically of limbs and of skin. An octopus, all limbs and all skin, asked to mend the things it is made of.

A witness, of a kind

There is one first-hand account worth mentioning carefully.

The missionary John Batchelor, who lived among the Ainu and published his ethnography in 1901, recorded a village shut down by a sea-monster attack. The thing was round, he was told, with large staring eyes, and it released a dark fluid with a powerful and foul smell. Three fishermen were left pale and trembling in their beds. The chief called a council, prayers were made, offerings prepared, and the good god of the sea was asked to drive the demon away.

Batchelor added his own footnote: the men said it was a devil, and he was inclined to think it was really a devil-fish — an octopus.

He never names the Akkorokamui. But what he documented is an Ainu community encountering an octopus-being and processing it in real time, with a date and a witness, which is rarer than it sounds.

The caveat travels with it, as it always must: Batchelor was a missionary, writing about a people he had come to convert, and his framing is his own. The Ainu tradition is not his to define. It is recorded here as what it is — an outsider's note in the margin of somebody else's belief.