Dinmenel and I noticed some interesting parallels between the description of the fall of the previous Kalpa in thehttp://www.imperial-library.info/content/mythic-dawn-commentaries, and the http://www.imperial-library.info/content/five-hundred-mighty-companions-or-thereabouts-ysgramor-returned Why do the Nords recognize the Kalpa system, unlike many other races on Nirn? Could it be they came from the previous world? There is some interesting evidence.
In the Mythic Dawn Commentaries, Camoran tells a story about a previous Kalpa called Lyg, ruled by the Dreugh. He claims that Destruction was invented by the Magne-Ge in order to stir up a rebellion to overthrow these Dreugh Slave-Lords. The towers are pulled down and the world is destroyed. Here is an abridged quote in case you don't want to look it up:
"I give my soul to the Magna Ge, for they created Mehrunes the Razor in secret, in the very bowels of Lyg, the domain of the Upstart who vanishes. Though they came from diverse waters, each Get shared sole purpose: to artifice a prince of good, spinning his likeness in random swath, and imbuing him with Oblivion's most precious and scarce asset: hope. For as Mehrunes threw down Lyg and cracked his face, declaring each of the nineteen and nine and nine oceans Free, so shall he crack the serpent crown of the Cyrodiils and make federation!
[...] by the magic word Nu-Mantia a great rebellion rose up and pulled down the towers of CHIM-EL GHARJYG, and the templars of the Upstart were slaughtered, and blood fell like dew from the upper wards down to the lowest pits, where the slaves with maniacal faces took chains and teeth to their jailers and all hope was brush-fire.
[...]Suns were riven as your red legions moved from Lyg to the hinterlands of chill, a legion for each Get, and Kuri was thrown down and Djaf was thrown down and Horma-Gile was crushed with coldsalt and forevermore called Hor and so shall it be again under the time of Gates.
Under the mires, Malbioge was thrown down, that old City of Chains, slaked in newbone-warmth and set Free. Galg and Mor-Galg were thrown down together in a single night of day
[...]Nothing but woe for NRN which has become The Pit and seven curses on its Dreugh, the Vermae NI-MOHK! But for it the Crusades would be as my lord's Creation, Get by the Ge and do as thou wilt, of no fetters but your own conscience! Know that your Hell is Broken, people of the Aurbis, and praise the Nu-Mantia which is Liberty!"
Why do I think this refers to Nords? First of all, we hear that the suns were riven as the rebels leave Lyg. What are the suns? It is explained in the 500 Companions text:
"Vrage the Gifted, born under the strange suns (meaning the sun of Ald Mora and the sun of Merethland)"
The plural suns represent Atmora (the Elder Wood), and Merethland (Skyrim). They have separate suns, but they seem to co-exist in the dawn as one dies and the other is born...at least long enough for someone to be born under both. This is anologous to the tales of the sundering of the Ehlnofey - those who would become the elves stay put, while those who would become human leave Lyg and end up in the "Hinterlands of Chill", which seems a likely name for Skyrim. How appropriate that the wandering Ehlnofey would wander in from another Kalpa altogether!
There are further parallels - the invaders are described as red legions, while "red" is referenced so much in the 500 Companions that there is a character "Olwep the Bald who couldn’t stand so many reds"! The legions are lead by the Magne-Ge, a "legion for each Get". Sure enough, 500 mentions some Ge and Get among the Companions:
"Kama-ge and Jori-ge and Ut Ge the Old Get [...] Jhun-ge the Tailor"
The character of Djaf who is overthrown in the Commentaries is present in 500 as well - in fact he cracks his face just like Lyg:
"Djaffidd, the whale-addict Gfeful who cracked his face across the ice laughing like a child at fair."
Horma-Gile might be "Hgil who used a ridiculously-large Totem of Kyne as a club," but it's not very clear. We also have "Dyssle’vehb the Stoic Shout, whose dewclaws were adorned in numantia-scratch", Numantia of course being the rallying cry of the rebels of Lyg. There is also a mention of Lyg itself in "and Kire the weird-looking lyg and Kye her sister (not weird-looking)"
So the Nords have thrown off Dreugh oppression, destroyed Lyg by pulling down its towers, and manage to voyage through the ensuing Dawn and eventually reach Skyrim with the help of some Drowned Lamps.
It's interesting that the final paragraph of the 500 is a repeat of the first, except all of the characters are dragons. We know that the Kalpas are supposedly ended by Alduin eating the world - now isn't it this suspicious? The Nords rebel, ending the previous Kalpa just as Alduin must, and appear as dragons, just as Alduin should. The first ship to make landfall on Nirn is called "The World-Eater's Waking". We also know that the Nords believe they are always the first to be eaten by Alduin. Perhaps this is because humanity IS Alduin - the force of change that ends up overthrowing the whole of reality.
If you don't think that's possible, recall that Mankar Camoran managed to take on draconic properties by embracing Destruction and returning to Dawntime as well - enough to wear the Amulet of Kings in fact:
"Roaring I wandered until I grew hoarse with the gospel. I had read the mysteries of Lord Dagon and feeling anew went mad with the overflow...Offering myself to that daybreak allowed the girdle of grace to contain me. When my voice returned, it spoke with another tongue. After three nights I could speak fire."
So, we have the World-Eating Nords marching to snow throat, seemingly intent on continuing their work of pulling down Towers and ending this world while it has hardly begun. They are Alduin, come to end Nirn. But something happens there - the cause is uncertain, but their dragon nature splits from their mortal nature. We end up with Ysgramor and Ysmaalithax, one of whom destroys the other.
I think here we have the Dragon War - Alduin has marched on Snow Throat, and rebellious humanity is face to face with their dominating dragon counterparts. It is the dreugh situation all over again. In fact, Mythic Dawn Commentaries explicitly comments on the similarity between dreugh and dragons:
"The Mundex Terrene was once ruled over solely by the tyrant dreugh-kings, each to their own dominion, and borderwars fought between their slave oceans. They were akin to the time-totems of old, yet evil, and full of mockery and profane powers. No one that lived did so outside of the sufferance of the dreughs."
Perhaps the shadow of their old masters is what causes the Nords to turn on their dragon counterparts. All we really know is that here on Snow-Throat, the Nords put off their destructive march and send Alduin into the future, prolonging this Kalpa beyond any seen before and creating the Time Wound. Well, that's enough rambling for the night. Send me your thoughts!