Xu Du is a murderer with antisocial personality. He thought he could change something by returning to his own place, but he didn't. He is as unreal as ever, lacking major emotional responses, uncoordinated in interpersonal interactions, lacking insight, etc. Senil is a king of the Sacred Stars. He is looking for his destined person according to the prophecy. He didn't expect that the other person is a mentally ill person. Maybe another person is his destined person? Well, the other one is just a weakling human.