In Book 4's Adventure Background, it is stated: "Though dominant for thousands of years after the war with the sivv, the kishalee civilization eventually deteriorated. For unknown reasons, its government slowly collapsed..."
My players have been looking forward to finding out what happened to the Kish(alee), but I think they would be pretty disappointed if I told them that the Kish(alee) civilization who created things that could last for millions of years collapsed "For unknown reasons".
So, I would like to ask... In your mind/game,
What happened to the Kishalee Empire?