Long, long ago, "besieging a hero" was considered a matter requiring a great sacrifice.
As long as the power disparity between both sides wasn't too desperate, a hero always had a chance to break out from the encirclement.
It wasn't for any other reason than that a hero could rely on absolute individual superiority to carve a broad path through the enemy lines.
When a hero slayed an enemy soldier, all he needed to do was to wave his hand, and this action didn't impact his forward speed at all. At that moment, his charge through the entire army was as effortless as if he were passing through a no man's land.
It's easy for a nail to be damaged when trying to puncture an iron plate, but when piercing tofu, the nail almost feels no resistance. Wear and tear can be ignored.
Within the army, there were martial studies experts lending support. But there weren't many of these experts. They couldn't cover the entire defense line and could only wait in fixed positions for orders.