When the Teacher and Student Get Serious

"Kai, watch out!"

The moment Ria's voice resounded in his head, he quickly raised his left hand, creating his Oscillation Shield to block an incoming attack from the left. However, he realized that the push was hard to the point it launched him to the wall almost instantly. 

By the time he realized that his Oscillation Shield, Ria already created a powerful shield that appeared from underground, redirecting the water to somewhere else.

Kai was astounded after he saw that Ra finally appeared on Eric's side again. He had known that his Sound Insulation Room to be a double-edged sword. Eric couldn't hear Ra while Kai couldn't hear as well. This was precisely the reason why Kai built a slightly wider room in this small underground area.