The most frustrating and horrible villains are usually the fake 'heroes' who can brainwash people and stupid 'heroes' who believe main villains and do self-righteous things to actual heroes in the name of justice... ugh I'm reminded of some annoying characters from Tate no Yuusha (the other 3 'heroes' + companions) and Tsuki ga Michibiku Isekai Douchuu (haven't debuted in manga iirc).
So just kill them right there. Can't use charm, when you're dead, and why would anyone 'care' about these 'heroes'? Only reason anyone lets them go is because of the charm.