The girl, Eva, and her group of men had become the highest authority in the slums, and they collected monster-protection money from every single person in the slums, claiming it was insurance to ensure they didn't get eaten by the beast that protected Eva. And since nearly everyone in the slums knew about the strange disappearances and mutilated body parts that are usually left behind after anyone tried to lay a hand on Eva, they all had no choice but to obey.
Anyone who didn't pay the money was given to the beast as its meal, and anytime the girl realized that everyone was paying the fee, she would increase the price the next day so that more people would not be able to pay.
Your gift is the motivation for my creation. Give me more motivation!