Quote
"I am Ampelas, who shaped the Blood in the paths of Emerlahn. The sorcery wielded by the Tiste Edur was born of my will."
They didn't get an aspect when working with K'rul - they've given their aspect to his creation.
As I understand it warrens are two things - places and sources of magic. I think warrens as places always existed ? Jaghut have one from before Imass, and K?Chain had one even earlier. K'rul made them accessible as magic sources - he created paths that can be used to access magic and connected them to warren with dragons shaping his blood in their image. He made it possible to access warrens you weren?t born into ? they were no longer properties of one race. It used to be Omtose Phellack - -Jaghut only, Tellan ? Imass only etc, but humans now can use any and many at once. Before Shaping of Blood they had to use holds ? they didn?t have warren to access.
I think that when dragons die the magic dies and the warren becomes just a place. Or at least it can no longer be accessed as path to it disintegrates.