Vigilantes

Vigilantes are people who voluntarily carry out duties usually done by Pro Heroes without paying attention to the law.

Due to the hero regulations and Quirk restriction laws, people are not allowed to perform heroic duties out on their own, thus, vigilantism is illegal.

History
The origins of Heroes can be traced back to vigilantes. When Quirks started to manifest, there was no organization controlling the people who used their Quirks to help others and take down the bad guys. Since these individuals were operating outside of the control of the government and law enforcement, they were declared vigilantes.

When the Pro Hero system was first put into place in Rhode Island, U.S.A. under the "Rhode Island New State Statute", one hundred and eighty-nine vigilantes were affected by this statute, with only seven being accepted as official Pro Heroes. Nowadays most of the vigilantes have vanished. The Hero Public Safety Commission originally secretly enlisted vigilantes to do their dirty work, like disposing of corrupt Pro Heroes, until they became too organized for the vigilantes to properly deal with, so the Commission abandoned that idea and instead focused on recruiting Pros to handle this job.

Most recently, Knuckleduster, Pop☆Step, and The Crawler had been regularly active in their activities to help people and dispense justice as the vigilantes of Naruhata.

Tenya Ida, Izuku Midoriya, and Shoto Todoroki technically acted as vigilantes during their battle with the Hero Killer: Stain, due to them not possessing their hero licenses when they fought him.

Becoming a Vigilante
In the current age, there is not much reason to become a vigilante when one could simply apply for a high school education in Heroics, or take a course as an adult to get your Hero license and become a professional Hero the legal way. Nonetheless, it does happen, despite vigilantism being illegal.

In some cases, it is a matter of principle, like how Chizome Akaguro dropped out of hero school because he was disillusioned by all of his classmates only caring about money and fame. He ended up becoming a vigilante and hunting down villains because he wanted to make up for the mistakes of hero society.

Other times, it can be a means to an end; Iwao Oguro became a vigilante after his hero career ended so that he could find his missing daughter and take down the group responsible for many of the misfortunes in his life.

Finally, sometimes a person can end up a vigilante by a twist of fate; Koichi Haimawari had intended to apply into a hero academy but missed his chance because he stopped to save a drowning child. Years later, he did good deeds around his neighborhood, which led to him saving a girl from a group of thugs. His innate bravery was noticed by Iwao, who chose to take Koichi under his wing, becoming a full-fledged vigilante.

Vigilante Debate
While the act of vigilantism is inherently illegal, the vigilantes themselves represent a gray line in the eyes of the law. There are times when a Hero is unavailable to stop the trouble, and the vigilantes' actions can result in lives being saved. It is because of this that a debate has persisted amongst those representing law enforcement on how lenient to be on a vigilante.

Pro Heroes, including Eraser Head, Midnight, and Ingenium, allowed the Naruhata Vigilantes to remain active, due to their actions primarily being in self-defense, as well as their compliance in seeking the Pro's assistance regarding any major trouble. Although, Eraser Head has stated that if a situation ever got too dangerous, or if the vigilantes started to abuse their Quirks, they would interfere.

Detective Naomasa Tsukauchi is on the side of wanting to follow the law by the book, and sees the vigilantes’ actions as going against it, frequently attempting to discover the source and to take down the Naruhata Vigilantes, only reluctantly letting it slide in dire circumstances. His senior, Eizo Tanuma, believes they are a necessary evil that if cooperated with, could be best utilized to track down underground organizations that not even traditional law enforcement can reach.

The argument was also brought up by Shoto after the Hosu Incident, stating that Native would've been killed by Stain had him, Tenya, and Izuku not interfered. The U.A. High School students would have faced severe punishment for using their Quirks without the proper authority or provisional hero licenses, as would their hero supervisors for not stopping them. However, given that there were only a few eyewitnesses at the scene, the police agreed to pardon their vigilantism on the condition that the truth of the incident be covered up by letting Endeavor take the credit for defeating Stain. This was also done to prevent Tenya, Izuku, and Shoto's hero careers from being ruined before they even began.

Following the Paranormal Liberation War and the collapse of society in Japan, many civilians have taken to vigilantism by defending themselves with their Quirks and salvaged support gear. This is due to many people now doubting the heroes and believing that they are unreliable and unable to protect them. While civilians have effectively fought back against villains, this has also caused mass collateral damage due to them being untrained. Furthermore, civilians have also begun attacking innocent people with Mutant-type Quirks, believing them to be villains solely due to their appearances and not trusting to hear them out.

Costumes
Vigilantes tend to wear costumes while they are out in the field, however not having access to support companies as heroes do, their costume is made out of their regular clothes and whatever they can get ahold of. In some cases, like with Iwao and Chizome, they may even resort to the black market like villains do, to obtain any resources they need.