I'm at chapter 20, nothing major, but this one thing is so ridiculous to me, if all he wants is to save his sister, why the fudge did he not select to become a s tier priest instead of Saint knight. He can save his sister and also live comfortably. Why was thinking about defense and stuff when his goal is not world peace or something like that. The world is not even ending anytime soon, again, very new so don't know if it will happen in the future.
PS I read a lot and a certain plot hole just eats at me during the entire series, so it's better if I just type it out.