Im partially expecting the plot twist if you think about the events of the battle it could be infered that that battle was the one that caused the twin secret art and the dragon Phoenix secret art to be lost
Which can further imply that it's quite possible since his soul clone was still around perhaps his soul could manage to survive aswell even as just a fragment
Perhaps
Big MAYBE
Old demon just can't remember but he is in fact the great demon god
This possibility stands until stated otherwise
