I mean, tsunderes are annoying and they're always at fault. The nephew's acting like his uncle's stupid, but...
"That coward...he ran away. Seriously..."
Uh...excuse you? He had been tied up and was about to be burned alive. Of FUCKING course he ran way. I mean, I guess he could have used magic to slaughter every last villager, but not sure not doing so makes him a coward.
Also, she started by insulting him three times, so...