While Hai Wuyu explained the whole story, the Grand Priest continuously channeled his own spiritual energy into him to keep him alive.
However, Hai Wuyu had suddenly transferred all of his spiritual power to Mu Yan; everything the Grand Priest did was merely prolonging his dying breath.
Furthermore, the Grand Priest himself had suffered excessive spiritual energy depletion during his battle with Hai Qitian; otherwise, he would not have failed to notice Hai Wuyu's act of self-sacrifice in the first place.
Chapter 89