An ordinary army could not form a military spirit, so their strength could not be gathered together. It was not enough to pose a threat to a Core. Even a Divine could easily kill their way out.
A single top-notch expert was enough to carve out a bloody path.
However, the Blood Barbarians were different. Not only did they have a military spirit, but their military spirit was also terrifyingly powerful. An ordinary Core could be killed with a single blow if they were unable to block the Blood Barbarians 'attacks.
This was the key reason the prince was so confident in encircling Chu Yunfan. Otherwise, why would he have done so knowing about Chu Yunfan's ferocious reputation and the number of Cores he had killed?