The Omens of Talum-Kai
Each of these nations is populated with mostly halflings, humans, gnomes and dwarves. This region is known for its bountiful farmlands and generally easy lifestyle. The boarders of each nation have slowly, over time, become a faded memory.
At one time, territory and land in this area was fought over brutally. It wasn't until Tol-Torak and his hordes of Drown Horse Archers scorched the earth of the five nations that their remaining leaders decided to knot their fortunes together to push back the overwhelming Drow Forces.
After pushing them back to the western side of Astor Istmus, they built a the Gates of Astor which held back the Drowden Hordes for almost 500 years.
Since then the nations have remained united, the five ruling families ending their animosity and instead ruling by committee, reveling in the shared prosperity their unity has brought to the land.