The Light Arrows were too fast, and the Quicksand Priest, not being a Spellcaster, could not cast magic quickly enough.
He had previously exhausted his energy twice, once to counter the flames and once to resist the Light Arrows. These two bursts of energy had left the Quicksand Priest seriously injured, and his magic power was still in chaos. He no longer had the opportunity for another burst of energy.
Even if he ceased casting the additional magic, he could only rely on his own ability to dodge. Unfortunately, this Quicksand Priest, as an ordinary priest, did not have as many enhanced equipment as Du You, and hence could not move quickly.
Confronted with attacks from all these Light Arrows, he had to rely on luck.
After a round of Light Arrows, Du You loudly taunted, "So, how did you like that attack? It felt good, didn't it? Why so silent? Should I go one more round?" Du You ridiculed loudly.