So Kaleshmar was an old and powerful empire ruled by three main races with balls ass crazy technology and supported by a bunch of slave races. One of those three main races were the Unglemell. They were sort of the leaders of Kaleshmar and were the oldest and most accomplished race that lived in the ancient floating empire. They were also pretty brutally oppressive to the races that they had subjugated.
The Unglemell were wise and powerful and long lived, but they really ran shit, unlike the Eldumans of The Old Empire in modern times that claim they ran shit way back when. If the Unglemell wanted to do something, they did it. The other races of Kaleshmar were free to disagree or try to veto the action, but if the Unglemell really truly wanted to do something, they did it and ignored the other races of their flying nation. Any decision they could get away with making for the other races, they made and more often than not, they were powerful enough to do whatever they thought was best and damn the consequences.
The Unglemell were complete and utter technophiles, and their technology made them a wee bit full of themselves. Eventually it came to a point where they were so drunk on power that they could not conceive of other races not wanting to be under their control. They were very aware of their power and the fact that they were right about things more often than not, and this led to quite a bit of arrogance. So, there, we have the arrogant "civilized" race bringing their wisdomousness to the uncivilized and "stupid" brutish races like the Abraxens and Uncout and various other Kaleshmar-based races.
The culture of the Unglemell put a lot of emphasis on technical expertise and combined efforts. They had a culture of reliance on one another, the slave races they had created and subjugated, and the other races of Kaleshmar. Despite their belief that they were superior to all other cultures, they believed that all members of Kaleshmar, whether slave or master, should contribute to the future of the nation, whether they wanted to or not.
So we have the Unglemell, who believe they know best and are so wrapped up in their awesomesauceness that they cannot conceive of other races, let alone members of their own race, not wanting to be part of their team. Then the prince and princess of the Unglemell decided that they were sick of this life of power and community, so they left Kaleshmar forever to forge a destiny for themselves that forced each member of their group to rely on themselves, rather than technology and the work of slaves. This schism shook the Unglemell to the very core of their society. The rulers of the race could not conceive of such a break with the way things were done in their empire, it confused them, stunned them, and left them vulnerable.
This confusion and upset in the hierarchy gave the Abraxens of the Ashlands the opening they needed to throw off the shackles of the Unglemell in their homeland and they were able to seek their own destiny free of their masters. From here it is a quick hop and a step to the poor decision making skills that allowed the Horned Man to pull his tricksy shenanigans that caused the eventual demise of Kaleshmar.