Last few chapters of this have been pretty crap. You made an mc that was op, and then create a situation where he seemingly can't save those he loves. Except he just had to put a barrier around the butler before he said anything. Stop any sound from coming out. If the slave magic isn't activated by sound, just put the barrier around his hand and remove it. The whole thing was just annoying to read if we don't feel the mc should actually be in such a dire situation. Shouldn't have setup the first parts of the story to make the mc so strong if this is where they were gonna take it.