Although the assistant claimed his strength was not high enough, he was still a Tier 3 Professional. Many people present hadn't even seen a Tier 2 Professional before, let alone Tier 3.
Du You also remembered his last opponent in the college entrance examination, who was also a Tier 3 enemy.
With a single, instinctual attack, not even using any special skills, he was unable to defend himself and had absolutely no resistance. This assistant, no matter how mediocre he was, could not be worse than that enemy.
Because of the difference in strength, those who were initially unruly became much more subdued. Du You suddenly realized that the assistant emitting his energy might have been intentional.
