This whole fucking manga is literally idiots doing stupid and rash things trying to be cool and manly. When in truth they behave like degenerated kids from Lord of the Flies with no morality. Not that adults are any better. But it's entertaining for sure.
It's actually a nice idea. Low scale conflict means his magic will be useful, and unless those with attack magic have AoE they are at disadvantage.
What are his other options?
Running away? His land will fall to ruin. And he cares about it, even if for selfish reasons.
Fight in a duel like a...
I think that creepy millipede (or some kind of monster from Japanese mythology, which name I forgot) should be used as censorship instead of stupid steam or beams of light.
I hope she will get heart attack and we will finish this shitty arc with a quick funeral. Really. There is no way that person with a mentality of a wooden block will change her ways after one talk.