They should have killed that self-proclaimed hero when they had a chance. Now he's gonna make much bigger trouble. This is why I don't like too-soft-hearted manga protagonists who indirectly killed people because they let killers go.
Wouldn't even say indirectly, since he was fully aware of what sort of person that wannabe hero is.. so it shouldn't come as surprise to anyone what he would do, especially since he's been after mc since forever literally only, because he didn't die after he tried letting him die in the labyrinth just because in the very beginning.. 😐
So far the manga has been heavily disappointing, when it comes to consequences, because the author doesn't have the balls to actually kill off characters, besides background characters that never said anything, or once they have been milked for a unholy amount of chapters
cough Onizuka
cough going as far as randomly throwing in a flashback before he dies 😮💨