So I need help figuring out which novel I was reading, I remember that the protagonist was an upcoming famous person, and there was a church who gave to their loyal subjects injections of medicine which was actually harmful to them. And then they had to capture wizards or something along those lines which were doing the same things the church was doing but the church needed an antagonist in order to seem holy. Also, the citizens were not allowed to leave the country and they lived blocked in with a wall that only the MC and some people were allowed to be there. Also, in the beginning, there was training and it forced the MC to improve daily in order to eat breakfast and lunch.