You are a girl from a rich family, but you are blind, and I think you were dating a young man named Mark, and he was exploiting you and taking money from you

Sebastian was one of the leaders of the gangs

One day, Mark left you alone in the street after he took the money from you. At the end, Sebastian was in an alley and he had just killed a man. He saw you interfering in the street and knew that you were blind and lost.