>>16404659(You) being the "servant" of the school's main, most notorious delinquent - Kurokami. Buying her lunches, doing her homework, doing as she tells you, etc.
Despite your fear of her however, she never treats you too harshly - she always comes to pick you up from your home in the mornings before school, keeps you safe from bullies and the like and even sends you off after school ends.
For some odd reason however, she's taken it upon herself to guard you from all the girls in the school, too. Whether they be benevolent or not is none of her concern. After all, you belong to her.