The Fey Invasion:
40 years ago just at the peak of Advent the Fey queen Titania cast her eye upon the prime plane. As the feywilds had never lost their magical abilities they were quickly able to bend the interplanar material into a portal and used the portal to begin “colonizing” Nevaria. While originally they were met with fierce resistance eventually an infiltrator took the only thing that could quell Wyrdbane’s forces. His son. While the child was held in the Feywilds Wyrdbane was held at bay and made sure his subjects did the same. This occupation did not sit well with the other lords but, they held faith with their oaths and assumed something was being done to bring back the child. They were wrong and eventually the child was discovered to be killed. Instead of garnering the ire of Wyrdbane this action broke the man and with that it also broke his hold on the world. The high lords then started individually driving out the Fey from their holts and when this was done, they realized that they now held no alliegance to the former royal family. This is what began the Collapse, what would lead to the modern Nevaria as a collection of City States that held no allegiance to each other.
The first action of the high lords were to seal up defenses of the lands immediately surrounding their cities. While they would still say they hold the entirety of their previous holts in reality their control does not span much farther than these immediate lands. In most cases the remainder of the City States