Posted 20 April 2007 - 10:30 PM
Kallor destroyed the continent of his Empire, Jacuruku, with unknown KCCM devices. K'rul took that damaged land and somehow created the Imperial Warren from it.
This seems to have, in effect, removed the devastated surface of Jacuruku and turned it into the IW. Which is why it is filled with the bones and ash of Kallor's dead imperial subjects, and the remains of Kallor's cities. Kalam even comes across KCCM remnants in DG or HoC, which is where the "destroyed with a KCCM device" speculation comes from.
Meanwhile Jacuruku was left behind minus some topsoil, and got the chance to regrow from scratch. I would assume it has done so to some degree by the main series, but clearly not enough to support major human civilisations and play a part in the main storyline, even to the minor level that Korelri has so far.