The tale shown is that of Izanagi and Izanami, from their creation of the islands of Japan up to Izanami's death from birthing Kagutsuchi (a.k.a. Homusubi), the god/incarnation of fire.

Moonspeaker said:

The tale shown is that of Izanagi and Izanami, from their creation of the islands of Japan up to Izanami's death from birthing Kagutsuchi (a.k.a. Homusubi), the god/incarnation of fire.

I had a suspicion it was that (though I definitely would have gotten the couple's names wrong and didn't know about the god of fire part). Thanks!

Semi-related: in hindsight I probably should have marked this page as Sensitive for that last panel like I did for the pages with the incident monster when she does her body modifications... but I don't quite know what that last panel is showing. I assume it'll be related to this story though

andlabs said:

I had a suspicion it was that (though I definitely would have gotten the couple's names wrong and didn't know about the god of fire part). Thanks!

Semi-related: in hindsight I probably should have marked this page as Sensitive for that last panel like I did for the pages with the incident monster when she does her body modifications... but I don't quite know what that last panel is showing. I assume it'll be related to this story though

From the myths of Kagutsuchi, several mountains and deities sprang forth from Kagutsuchi's dismembered remains and blood, respectively. I'm guessing that's what it is.