Xavax impending demise, also causes many of its nobles to seek new home in the north. Inevitably this will lead to First Oligarch demise as well as the north realms they will be joining, are going to strengthen them. I maybe forecast this situation but that's what I think is going to happen. You do not suddenly expect former Xavax nobles to join its enemies realms.
In the end, the north will have to consolidate. As would be the south when they absorb Xavax lands. Maybe the south realms will fight for the spoils of Xavax lands.
