There was no official conclusion as to whether the third uncle in Grave Robber's Chronicles was dead or not. As for the person wearing the Third Uncle mask, there were many possibilities in the novel. The most obvious one was that this person might be Wu Xie's grandfather, Wu Sansheng's father, Wu Old Dog. In the novel, Old Dog Wu was portrayed as a mysterious character. He wore the mask of his third uncle and acted strangely. He might be his third uncle's agent in the underground world. However, this answer was only based on the description in the novel. The actual situation might be different due to different interpretation.