Zhao Hai's sudden attack was beyond the expectations of the Alliance and the sacred Institute. The Alliance had thought that Zhao Hai wouldn't attack them since he had left. The sacred Institute hadn't expected Zhao Hai to attack them either. After all, the sacred Institute had attacked the Alliance, but they hadn't attacked Zhao Hai and the other city-states. They had deliberately avoided Zhao Hai and the other city-states. He didn't want to get into a conflict with Zhao Hai and the others, but Zhao Hai still made a move.
Of course Zhao Hai would take action. Not only did he have a grudge against the sacred Institute, but he would also be stupid if he didn't take action now and allowed the sacred Institute to take care of the anti-sacred Institute Alliance.