To my understanding there are mortals that live in Oblivion planes. In Shivering Isles for example according to wikis, but I personaly didn't play that one.
What is their story, how they fit in the lore? I'm not talking about heroes that visit those planes, but the ones that live there. Were they created by the Princes of each of the realm they live in or all originated in Mundus? They have full life cicle there, they are born, reproduce and die there?

You should read the Infernal City and its sequel. Both describe mortals living in a realm/"bubble" of Oblivion. It goes into great detail about the death and life cycles of the mortals as well.

As to the origin of these folks, I either don't remember or it didn't say.

Mortals mostly originate in mundus. The Shivering Isles may have some native mortal creatures, like the Grummite, but the Grummite may have come from Akavir for all we know.

I forget, is Mundus the same thing as Nirn? I thought Mundus included the other planets and moons? Wasn't there a theory floating around about how before Nirn, several planets existed with their own life before they combined to what is now Nirn?

My understanding is:
Mundus is the entire mortal realm

Nirn is the planet, and the center of the universe.

As for multiple worlds, several lore sources mention "The Twelve worlds of Creation," which become sundered and then hodge-podged into Nirn.

The way I like to think of it is: Mundus is the "solar system" (includes Nirn, Lorkhan, the plane(t)s of Akatosh, Mara, etc), with Oblivion being "deep space" and the Oblivion realms being "extrasolar" plane(t)s.

Though this doesn't really jive with the idea that Reman's lunar colony expeditions needed permission from the rulers of Oblivion to reach the moons...

I've always figured that the Daedra have the best access to space ships.

I think since the Oblivion planes are literally the Daedra Prince that controls it, anything found within it ("naturally") is likewise part of the Daedric Prince.

Mortals that aren't simply fragments of a Daedric Prince would have to have migrated to the Oblvion plane from somewhere else.

You might be interested in the Dremora, maybe? I know there is a bit of lore on them but I need to look it up before I can make any statements about them.

Pretty sure the dremora are daedra? Unless I missed your point.
I think most if not all of the mortals in SI were supposed to have ended up there somehow but originated in Mundus.

Depends on the Prince. Their realms, their rules. One woman in the Shivering Isles is over a thousand years old, and she was an Imperial. Some "hospitable realms" include Azura's Moonshadow, Shivering Isles and I think Sanguine may have hospitable places, since he has many pocket realms. Hircine's Hunting Grounds is always in motion, meaning you're always chasing something, or something may be chasing you providing your human. I think it may be hospitable to werebears and werewolves since it's an entire landscape of forest, savannah, tributaries and canyons.


I don't know if reproduction is possible in the Realm of Oblivion, let alone if the person died in Nirn and went there following death. But I don't know, I'm as equally interested as you are.

Outside of Mundus, The Aedra's rules rules don't apply. Life and death and all that stuff is at the whim of the Prince (notice how in Camoran's Paradise, anyone who dies just comes right back).

http://imperial-library.info/content/vitharn-fall.

Thanks for the link. Puts that speculation to death, doesn't it? I was going to mention Mankar's Paradise(Paradise being a lie). Same could not be said for the Shivering Isles, people die there, and some never come back as flesh.

Reproduction cannot be said for all realms, however?

What I find curious is that even if the mortals of the other realms do not reproduce through copulation between two mates, they are still capable of (and indeed participate in) sixual activity. This makes me think that these mortals were once capable of reproducing through copulation.

Well, the plants, fungi, fish, animals, and Grummites are all mortal. The obviously originated in Mundus, but they may have been in the Isles for thousands of years.

As I said, it's up to the Prince. On Mundus, life and death, love, etc, are controlled by the Aedra since they're bound to the mortal plane. The Realms of Oblivion are not part of the mortal plane, so the Aedra have no sway in them. Life and death and everything happens because the Prince wants it to. If the Prince doesn't want it to, it won't happen.

Though maybe there's some loopholes for mortals that enter Oblivion realms and haven't opened themselves to the ruling Prince... I'm not sure on that.

Reproduction might have less to do with biology than we are aware of. Souls get recycled through the dreamsleeve or some alternative to it. So what happens if a soul can't get to a fetus in a different realm?

And I'm not sure, but what you described was also the case in Umbriel, from the TES novels. In this case though, I was under the impression that the mortals living in Umbriel had been copied by the Sump or whatever, none of them were indigenous to the realm. They were replicas of beings from other realms. So they could be some weird artificially tampered with beings that reproduce as Umbriel sees fit.

The way it worked also seemed to keep the population from getting out of hand.

"but I personaly didn't play that one" Well you need to! lol

And no the Princes did not create them. They cannot create anything. They can only take and change. The mortals living in their realms were born within the Mundus and left it for Oblivion.

Well, that or their ancestors left mundus and they were born there.

Don't mortal souls have a hard time getting to Oblivion realms? Or did I misinterpret the ingenium/sump from Umbriel?

Mortals have a relatively easy time going in oblivion, both in flesh or in spirit. It's much harder for Daedra to do the opposite. Umbriel is a unique case in a lot of ways. It's ingenium was more or less a mini-dreamsleeve, and it's presence in a bubble of Clavicus Vile was unprecedented.