Quirk

A quirk (個性 Kosei), also known as Meta Ability (異能 Inō) is a special, superhuman ability. Along with being generally unique to each user, quirks are compartmentalized into multiple categories: Emitter, Mutation, Psi, and Transformation. Approximately 80% of the world's population is a quirk user as of 2220 AD, or 178 QM.

Emergence (2042-2060)
On January 1, 2042 (178 QM), a baby was born in Qingqing, China with the ability to emanate light from their body; this baby would later become known as the Luminescent Baby, the first officially recorded child born with a quirk. Soon after, many people around the world began being born and manifesting different kinds of superpowers.

Even almost two centuries later, the exact cause of the quirk phenomenon is unknown, but there are several theories, one of the most prominent being that the development of quirks was caused by a virus carried by mice causing mutations that led to the development of the superpowers, many of which, in the first few years, centered around heat and light. These powers were initially referred to as 'meta abilities' before later being called quirks.

Chaos Period (2060-2080)
As the first generation of quirk users came of age, with them came the problem of integrating them into society. A massive breakdown of society plagued society for almost two decades as a series of wars and social upheaval threatened to tear humanity apart; quirked fought quirkless; quirkless fought each other; quirked fought each other. A sudden onslaught of criminals empowered by their superpowers emerged while the still-dominant quirkless people actively utilized the rule of law to discriminate against people with quirks. Severe restrictions were placed on the quirked to try and reel in the criminals decimating communities with no way to fight back.

World War III (2081-2098)
Tensions exploded with the assassination of the first quirked president of the United States of America, Elizabeth Fairview. The United States declared war against England, who evidence suggested had ordered the hit through MI6. England allied with Russia, Italy, France, China, most of West Asia, and Wales while the United States allied with Mexico, Ireland, Canada, Scotland, Japan, South Korea, and Germany. The vast majority of Africa, Central and South America, Southeast Asia, Oceania, and Central Asia chose to remain neutral, along with much of southern and central Europe. The war then was set between the pro-quirk alliance (then named the Sunrise Alliance) and the quirk-control alliance (then named the Bronze Alliance). While nuclear weapons were threatened several times, the thread of mutually assured destruction prevented the use of the weapons. Instead, both sides, including the Bronze Alliance, primarily used quirked soldiers as well as smaller-scaled super weapons.

The resulting war ended with massive damage and technological decline in most participating countries, leaving the rest of the world to advance quickly while the countries involved scramble to piece back together their economies and country.

There was no clear winner of the war, and depending on where in the world you go, you would get different answers on whether the Bronze Alliance or Sunrise Alliance won.

Dark Era (2099-2140)
By 2100, almost 40% of the population had a quirk and it quickly became clear that even almost a hundred years later, society had not changed enough to allow for super-humans to exist comfortably side-by-side with ordinary people. A series of coups and revolutions overtook most of North America, East Asia, and Europe as they tried to recover from the last world war as well as the booms of quirked humans. Meanwhile, in the rest of the world, a variety of artistic, technological, and cultural revolutions took place. Nigeria became one of the world's art centers alongside Peru, and Brazil and South Africa became world powers in the 2110s.

Despite the blossoming and rapidly advancing technology in most of Africa, South America, West, South, and Central Asia, and Oceania, global warming was beginning to really hit its stride, with massive amounts of climate refugees fleeing ocean-side nations. Oceania especially was struck hard and thousands of Emitter type quirk users were brought to the region in an attempt to raise the islands and help fish and coral populations recover.

In northern Africa, the Great Green Wall of the Sahel, led by the African Union, was finally completed in full with the help of quirk users in the region and the desertification of the region was slowed to a stop. While the wall itself and the major goals were complete by the 2040s, the reversal of desertification and following projects were not until this time. Africa and the African Union led the charge against climate change during this time period.

A pandemic emerged in England during the 2120s and spread throughout much of Europe and the Americas before striking almost every country on Earth; striking primarily young quirk users, it carved a swathe through society. Later that decade, a massive solar flare crashed computers and the cloud, leading to the loss and corruption of billions of files. The plethora of natural and man-made disasters collapsed much of the technological progress worldwide, regressing almost every region back to the mid-2000s.

However, things began to look up towards the beginning of the 2130s as almost a century of active anti-climate change programs finally began to reverse the effects of global warming.

By 2130, almost half of the population had a quirk.

In the mid 2130s, war broke out once more, this time between China and Japan. The conflict was fast and dirty and resulted in the agreement to no longer used meta humans in martial combat again, as the human rights abuses were too high to stomach. Many other countries in the regions followed suit and the movement spread worldwide, with the vast majority of nations agreeing to remove quirked warfare from their arsenals.

Vigilante Era (2140-2180)
As the population of quirked individuals increased and the quirkless decreased, the rapid unrest and crime in most major cities continued, but for the first time, there began to be a concentrated effort of citizens taking matters into their own hands. The first 'Heroes' appeared in the form of Vigilantes and ushered in the Vigilante Era. At first, the vigilante movement was sporadic and unorganized; it wasn't until the 2150s that vigilantes become an important and integral aspect of everyday life in most cities. It was during this time period that All for One appeared and became a symbol of unity in society. He used his quirk to remove the quirks of those who did not want them and gave quirks to those who did. Law enforcement in many countries globally began to create draconian laws prohibiting the use of quirks in public as they removed their only ability to utilize quirks on the job. In this vacuum, the first Pro Heroes arose in the late 70s and early 80s. Authorizing the use of powers that could so easily kill, however, was a greatly criticized decision at first.

Era of Heroes (2180-present)
By 2185, over 75% of society possessed a quirk and yet the vast majority rarely used them outside of classes and heavily structured activities, fueling the villain industry outside of the typical criminal enterprises that made up the bulk of villain activity.

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 the governments of a number of nations for several years before ultimately suffering defeat and going underground.

All Might rose to power in the 2190s and came to prominence as the Pro Hero, coming to define an entire generation.

As of 2220 (178 QM), almost 80% of society possess a quirk.

Information
Quirks are said to be the next stage of evolution in the human race. It is possible to diagnose a person as possessing or lacking a quirk by analyzing the presence or absence of an extra joint in their pinky toe. People with only one joint will develop a quirk while having two joints indicates that the person is quirkless.

A person's quirk will normally manifest around the the age of four years old, although, it is possible for a child to be born with their quirks already manifested.

Although rare, it is possible for animals to have quirks.

Quirk levels can be measured, though only All Might's have ever been shown, being at 15,000 AP at his peak and reaching a low point of 2,500 AP in the present.

Quirk Factor
The term "Quirk Factor" refers to the collective physical and genetic traits that compose a person's quirk. This includes the primary quirk power as well as all the biological mechanisms that allow said primary power to function properly.

Under special circumstances, a second quirk can be added to a persons genetics. There is a chance that the two quirks may merge, becoming a new quirk, as was the case with One For All.

Certain quirks, such as Erasure, are capable of temporarily halting the expression of the Quirk Factor, rendering the quirk unusable for a short period, but not affecting the Quirk Factor otherwise. There are other quirks, however, that are able to directly damage the Quirk Factor of a target, preventing the quirk from being activated until the user manages to naturally recover. It's also possible that a Quirk Factor can be damaged beyond recovery, causing the quirk to be permanently suppressed.

Heredity
Quirks are inherited genetically through what appears to be Mendelian inheritance.