Dangerous Lesson.

Their swords were their hammer, and each other were their metal blocks. But instead of diffusing the backlash between them, they kept it within the fight for their own use. This meant that the backlash was increasing between them. 

This backlash was being passed from one fighter to the other. But it couldn't continue indefinitely. The first person to fail to redirect the backlash would have to bear the backlash for the two of them. 

By that time, the backlash would already be too big for both of them to handle safely. So the person who bears it will definitely be terribly injured. 

This was the goal. It was to outlast the other. The person who endured the longest would win. 

But this wasn't easy. Redirecting the backlash is a skillful matter, but it is also taxing on the body in terms of stamina and stress. 

Arthur has the advantage in stamina, but he is lacking in skill, which caused his body to bear more stress than Brooks.