I hope that there is a technique that allows him to kill the sealed demons there. It's stupid that he can't kill them even though they are already sealed.
bruh of course there is..
don't forget the prev chapter when the past life Yuan take over Yuan's Body and toy the demon to death using the other sealing technique.
Not sure why people are worried about him causing trouble inside the library. I would expect that the âtroubleâ anyone would cause would be after leaving and having a demon find them and read their soul to figure out how to defend against the techniques.