Yes, definitely a delinquent school. I wondered why the MC chose a school like this, but maybe it was his parents. They could be some kind hardliners who weren't happy with the son's timid attitude and thought a rough school will get him into shape. Not an exceedingly wise plan.
gotta love her committing , i wonder how many other she tormented before having a favorite 'toy' (tho interesting she had some assistants willingly going along)
or a cult leader, she could just be 'disciplining' her to get her to behave versus fully disposing her , an army of mindbroken slaves would be quite a thing to see at the end