I knew that look.
This empty eyes and tired expression master makes whenever he was alone. Master has lived a very long life, he is so old that he even helped to evacuate humans from the upper regions. do people make that face when they are tired of living?
But the expression master wore that day was a bit different, he looked like someone who has found hope. I couldn't understand what that face meant, but I did after waking up later.
He killed himself.
He didn't need to fight that monster by himself. Brother Ba might have some self-confidence issues, but he is very strong. I am sure master told him something like ' help the citizens ' or ' you shouldn't let people see your true form ' and ordered him to retreat. Brother Ba would never ignore a command from master.