Grey was secretly preparing another array with each attack he unleashes. As long as the young man continued dodging in this manner, Grey would complete a terrifying attack array that might have the power to one-shot this young man.
With every attack he sends out, he would take out a portion of it and infuse it with the array he was creating. Once the array was finished, the attack power might even exceed the Sage Plane realm. This was all on the premise that the young man continues dodging and blocking which he is currently doing.
The young man didn't want Grey to hit him with any attack since it would be dangerous for him.
Grey didn't give him any chance as he continued his onslaught of attacks. Since the young man wanted to keep up with this, he didn't mind entertaining him.
The young man continued defending as Grey continued attacking.