From MoI:
From HoC:I am Treach - one of many names. Trake, the Tiger of Summer, the Talons of War. Silent Hunter. I was there at the end, one of the few survivors once the T'lan Imass were done with us. Brutal, merciful slaughter. They had no choice - I see that now, though none of us were prepared to forgive. Not then. The wounds were too fresh.
Gods, we tore a warren to pieces on that distant continent. Turned the eastlands into molten stone that cooled and became something that defied sorcery. The T'lan Imass sacrificed thousands to cut away the cancer we had become. It was the end, the end of all that promise, all that bright glory. The end of the First Empire. Hubris, to have claimed a name that rightly belonged to the T'lan Imass.
All well and good so far. The First Empire of Dessimbelackis did some serious ritual, turning themselves into Soletakens, and shattering the warren.Febryl nodded. "The First Empire of Dessimbelackis, Kamist Reloe, was not the first. That belonged to the T'lan Imass. There was little, it is true, that you or I might recognize as being...imperial. No cities. No breaking of the ground to plant crops or irrigate. And its armies were undead. There was a throne, of course, upon which was meant to sit a mortal - the progeny race of the T'lan Imass. A human. Alas, humans viewed empire...differently. And their vision did not include T'lan Imass. Thus, betrayal. Then war. An unequal contest, but the T'lan Imass were reluctant to annihilate their mortal children. And so they left-"
"Only to return with the shattering of the warren," Kamist Reloe muttered, nodding. "When the chaos erupted with the ritual of Soletaken and D'ivers."
But then there's these, from MT:
And the fact that the Edur are the rulers of Emurlahn is pretty clear in numerous passages."No, my friend, with this day's victory this world lies before our feet. Here, you shall not suffer from the civil wars that plague Kurald Galain. And I and my followers shall escape the rivening that now besets Kurald Emurlahn-"
Silchas Ruin snorted. "A rivening by your own hand, Scabandari."
So who shattered the warren???
Unless the answer is still coming. Entirely possible. And these two things could be combined. For example, an Edur could have helped Dessimbelackis cast his spell.