@blight @RUSHIFA
Simple. They were unable to build a solid society. and it doesn't matter how strong each individual is as long as you cannot even get through a comon bases of morality like:
is slavery wrong?
how about mind control?
removing memories?
buildjng hidden chambers full of monsters in middle of school?
building a school next to a monster forest?
You cannot conquer anything, if your people are devided on morality.
Their criminal justice system was also pretty fucked up. You can't cast a spell that directly causes pain without physical damage, but you can burn someone with a fireball or other stuff. Then when you go to prison, there's only that one prison with dementors that steal your soul.