I think it's a designated term for this kind of character. Usually they use their own money to purchase foods during lunch in a school setting for the bullies.
2 Answers
Bread Shuttles. Korean. Not Japanese.
빵셔틀
[ppang-syeoteul] Term literally meaning ‘bread shuttle.’ Usually used at school, where one student is picked on and/or bullied to do the errands for people who are in a stronger position than they are.