Heaven and the Unknown Lands.

Soh is said to cross the bridge between heaven and earth.

Although I sometimes interpret this literally depending on the theory I'm considering, another meaning can be that she's coming from a different world.

Cursed Soh is said to rule from the heavens. But these plaques are a little subjective. If a god comes from somewhere, we might call it 'heaven' by default. Heaven can just be another world.

Kami are said to inhabit parallel world to our own, one that mirrors ours.

After some consideration, 'heaven' is here:

It looks like the peak of the mountain, doesn't it? As the sun is rising...

The place the Maiden is in when she's enshrined as the spirit stone and Goddess.

It's actually the same place as the Unknown Land.

The Unknown Land becomes corrupted during our cycle.

Soh is horrified when she sees what the place has become. It's crystallized, like defilement...or spirit stone? This barrier is similar to the one used to protect oneself from Seethe. What happened in this world?

I wrote more on this world in a longer post featuring multiple theories I'm still working on... so I'll paste what I wrote:

In the true ending, when Soh enters the Unknown Land, this is the same place. Only it's been completely distorted. The kaleidoscopic pattern is all over and has become hard and crystallized, like defilement. There's no more beautiful scenery. Instead, we're looking at the remnants of the main shrine.

When something is crystallized, it remains in stasis. Much like how the mountain was stuck in a cycle, never truly advancing forward . Every time the mountain is rebuilt, the Seethe tear it down again. There is no advancement. Everything is torn down to nothing. Villages must be rebuilt.

Kaleidoscope represents the Goddess's power...and here it takes on a disturbing appearance. The floor is wet and reflective, much like 'Heaven' was. It seems a cursed image was reflected multiple times because of the reflective surfaces?

When Cursed Soh is defeated, the pieces of the kaleidoscope break apart and turn into the bright light that empowers Soh.

Once purified, we see it's the same place as 'Heaven'!

Take a peek into the shrine.

Upon entering, I was hit with anxiety. It's very claustrophobic and deeply unsettling. Kunitsu-Gami has always had horror elements to it that get easily overlooked.

Onto this idea of it mirroring our world...

I accidentally put a snare trap when I was running around before entering the stage.

It appeared in the Unknown Land!

I tried it again. Here's a video:

The Unknown Land is on the same terrain as the main shrine.
(Which is probably obvious as we can see the shrine in the background of the Unknown Land)

But could this mean that 'the Unknown Land' is part of the mirror world kami live in?

I mentioned they live in a parallel world to ours, described as mirroring ours. Did the game decide to play with the idea of mirrors in relation to this?

This strange movement...

Same type of crystal as what's in the masks.

Doesn't it remind you of the way Soh's barrier moves?

On the mikoshi...

祓. Ritual Purification/Exorcism. Why is it crossed out on the mikoshi but not the shrine?

The drums that are beside the shrine in the real world are replaced with these statues that can be seen outside the real world shrine.
(not really important but at first I thought they had come from nowhere and had meaning. But these statues exist in the real world, just outside the shrine)

Where did the very first Soh come from? 

What if the Unknown Land is a reflection of Heaven, where the Goddess resided before she descended? And the Maidens live in a makeshift Heaven, a place designed to keep their spirits?

As in Heaven is where the Goddess lives and its reflection is where the Maiden's spirit rests. Which means the Soh met in the normal ending is just a reflection of the Goddess.

But I don't know...the Goddess herself became defiled so this can't be right. But Cursed Soh is an 'image of the Goddess entangled with man's impurity'. Is image used because it's one part of the Goddess and Soh, the other, isn't impure?

It could just be a world that's the resting place of the Maiden's spirit when she becomes the spirit stone and nothing more.

In the Japanese translation of Cursed Soh's plaque, it can be translated as 'image of the god' or just the god itself. But I'll use the English translation.

I want to think on the idea of 'images'...

Cute photo of Yoshiro in the Unknown Land