I honestly can't even fault him for his mind snapping. We're continuously shown more and more evil things they did to him and his companions, even though he and his companions literally saved their kingdom.
It's so gory. And I love it so goddamn much.
On another note, i love how hypocritical the princess and everyone under her is. I mean they even won't blink an eye making excuses even after they themselves announced their own crimes