The first person to manifest a Quirk was a
newborn baby in the city of
Qingqing; their ability was to emanate light from their body. After that incident, many people around the world began to manifest different kinds of special abilities. While the cause of the Quirk phenomenon is unknown, it has been theorized that the development of Quirks was caused by the spread of a virus carried by mice.
[2] Currently, around 80% of the world population possesses a Quirk.
[3]
The dawn of this extraordinary era was marred by a breakdown of society caused by the sudden onslaught of criminals empowered by their newfound "superpowers". These superpowers were first referred to as meta abilities before later being called Quirks.
[4] In this time,
All For One became a symbol of unity in society. He used his
Quirk to remove Quirks from those who did not want them, and give Quirks to those that did, under the guise of returning society to its prior state of humanity. In this way, he gathered followers who were loyal to him, allowing him to act out his ulterior motives.
[5]
The era of Vigilantes.
As chaos and unrest ensued due to the outbreak of Quirks, ordinary civilians with their own Quirks decided to take matters into their own hands to bring order to society and thus the first "heroes" appeared in the form of
Vigilantes and thus beginning the Vigilantes Era.
[6]
As society adapted to the new status quo, the
Police Force moved to prioritize leadership and to maintain the status quo, and as such, decided not to use Quirks as weapons. To fill that void, the profession of crime fighting Quirk users,
Pro Heroes, began to exist which caused the Vigilantes to slowly disappear. Authorizing the use of powers that could so easily kill, however, was a greatly criticized decision at first.
Over time, it came to garner public support due to the fact that the first people to work professionally as heroes acted morally and upheld the law.
[7] However, some members of society were not happy with the the governments' regulations on Quirk usage as they believed that the use of their superhuman abilities should be a right.
[8]
A group of Quirk users known as the
Meta Liberation Army, led by
Destro, had tried to stop the passing of regulations that would restrict Quirk usage. They rebelled against several governments for years before ultimately suffering defeat.[9]