Vigilante 

When Ji-Yong Kim was a boy, his mother was murdered. The assailant was tried in the court of law but served a mere three and a half years because he “deeply regrets his actions.” 17 years later, Ji-Yong is a college student, studying to become a police officer. But on the weekends, Ji-Yong hunts down ex-convicts released by a justice system that has failed to protect the victims, taking justice into his own hands to make up for its shortcomings. (Source: WEBTOON, edited)