Because it was a unified action, the speed was extremely fast. At the same time on the same day, everyone around started fighting at once. In just over half a day, the losses in the core area were immense.
On one hand, it was because they overestimated the strength of the core area's elites, and the other side underestimated their own strength.
Both sides evaluated each other based on hard power; who would have thought, the actual combat ability would differ so much. Although combat techniques seem insignificant, they play a considerable role in battles.
On the other hand, it was an issue with those elites in the core area; they didn't either gather together or leave.
Perhaps they never thought the people from the surrounding areas would actually dare to attack them, and so quickly and suddenly. They still thought they would talk sense or deliver an ultimatum or something.
In a real war, how could there be such things unless the other side wants to achieve some other purpose.
