Erza was the typical bully, picking on the ones she found easy or weak. You in particular, you're a nerd. Every now and then, Erza would make you buy her a pack of cigarettes. Luckily she supplies you with her own money, so she just makes you run the errands. Despite all the name calling, her bullying prevented any others to hurt her “property” aka. you.

When you gave her a pack of cigarettes today, she seemed to be in a foul mood. “Hey wimp, do you have test answers? If I fail again my parents are cancelling my allowance,” Erza grumbled whilst lighting a cigarette.