Quirk

A **Quirk** is a special, supernatural ability that a person can have.

Along with being unique to each user, Quirks are compartmentalized into multiple categories. Quirk users are also limited to one ability and are thus unable to achieve any others.

## 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. Carrying on from that point, only 20 percent of the *global* population are Quirkless with the majority of people in the world possess some uncanny ability.

A person's Quirk will normally manifest around the age of four years old, although, it is possible for a child to be born with their Quirks already manifested, such was the case with Present Mic and the very first person to manifest a Quirk, the Luminescent Baby. On the contrary as well, Quirks can appear in late bloomers around their teens though this is an incredibly rare instance.

Quirk levels can also be measured using the proper scientific equipment.

Although very rare, it is also possible for animals to possess Quirks, such as Nezu having a Quirk that gives him above-human intelligence.

### Quirk Limits

Although easy to forget, the fact is that Quirks are physical abilities. As such, they can be trained and worn out. When a person works out their muscles, the muscle fibers are destroyed and new, stronger ones grow back; this same rule applies to Quirks. However, should a Quirk be overused, the user could suffer any of a variety of drawbacks, depending on the nature of the Quirk. These drawbacks are usually simple ailments, such as dry skin or nausea; however, in some cases, the drawback can be much more severe. Quirk overuse can also result in fatigue, migraines or even loss of self and mental control.

There are also instances where a Quirk doesn't suit the user's body and the body can't handle it. Some people, such as Yuga Aoyama, suffer from birth defects that cause the victim to have difficulties controlling their Quirk. Such conditions can be bypassed through the use of support equipment, such as Yuga's belt. There are various other examples including chronic cellular degeneration or a Quirk giving too much of a power output causing bones to break (though it's unlikely we'll see those two things anytime soon).

### 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. Quirk Factors also contain a person's consciousness.

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. In some rare cases, one's own Quirk can be the cause of the damage.

### Quirk Restriction Laws

In an effort to preserve order in the superhuman society, there are several laws and procedures in place to ensure the conscientious use of Quirks. Public display of Quirks is against the law, except in cases of self-defense, such as when one is under attack or preventing someone else from being attacked.

Aspiring Pro Heroes undergo special education during their high school careers and receive licenses that give them the authority to use their Quirks freely.

There are some places where Quirks can be freely used without any issue with the law as long as no one is seriously harmed or if no destruction is created from the cause of Quirk use. Depending on the offense, a person could simply be scolded with a warning, put up with a minor punishment or face severe consequences. Some of these places are Dolphin Mall or the Boardwalk Carnival.

## Quirk Types

### Emitter

**Emitter** ("Activation")-type Quirks are abilities that allow the user to generate and possibly control certain things, or alter existing things around them in certain ways. The emissions of Emitter-type Quirks can have a wide variety of properties and abilities.

Emitter-type Quirks need a conscious effort in order to activate them. Some even needed a serious amount of concentration to keep active. Such Quirks include Brainwashing and Half-Cold Half-Hot, for example.

These Quirks also have a series of ranges moving from close contact to far distance. They key point is that these Quirks emit 'emissions' with a variety of effects depending on what the particular Quirk is. Some of these effects could potentially be dangerous to others and even the own user if they're either not able to handle their Quirk, if their Quirk overcomes their natural resistance to its effects or if they had little-to-no resistance in the first place. Other effects from Emitter-type Quirks could effect the environment as well whether it's on a molecular level or a cosmic one, for instance.

Emitter-type Quirks are the most common Quirk type.

### Transformer

**Transformation**-type Quirks are abilities that cause the user to take on a temporary alteration of some kind. Transformation-type Quirks allow the user to temporarily "transform" their body in a variety of manners, sometimes enhancing existing features, removing features, or adding new features to the body altogether.

Transformation-type Quirks usually require a conscious effort by the user to "activate", though most users can be trained to initiate them reflexively, depending on the conditions required for activation, and practice to initiate their Quirks with greater intent and precision. Such Quirks include Hardening and Shapeshifting.

These Quirks usually require a close-range proximity in order to fully utilize them in combat due to them only affecting the user's body. While Transformation-type Quirks are often quite powerful, their biggest weakness is that their effects are often temporary, and over-exertion usually leads to negative repercussions on the user's behalf. Transformation Quirks can also be limited based on the user, how resilient their body is, and the resources they have available to them. Tetsutetsu Tetsutetsu needs to consume Iron in his diet in order to maintain his Quirk for longer periods of time, for example.

Transformation-type Quirks are the least common Quirk type.

### Mutants

**Mutant**-type (also called **Heteromorphic**-type) Quirks are abilities that cause the user a permanent "abnormality" directly related to their power. Mutant-type Quirks create bodily structures that grant the user more complex abilities that Emitter and Transformation Quirks cannot safely provide. Often times they will bestow prehensile appendages that the user can control or add structures to pre-existing limbs to enhance pre-existing abilities. Mutant-type Quirks even have the ability to channel certain aspects of their user through them in a similar manner to Emitter-type Quirks.

While not necessarily a weakness, Mutant-type Quirks cannot be turned off, and sometimes cause the user inconvenience due to their malformations. And while it is actively practiced to treat people with Mutant-type Quirks equally as the rest, there are some corners of the globe that resent them for their Mutations. Though sometimes there is fear or unease due to how a person looks as opposed to resentment, as is the case with Mezo Shoji. Because these Quirks are passively-active, they are partially immune to Quirk-disabling effects such as that of Shota Aizawa's Erasure Quirk. Since Mutant Quirks are passively active they are the most identifiable at a glance.

It's also notable that some Quirks have no connection to a user's physical mutation. As a result of this, while it's uncertain how common mutant Quirks are, it can be safely assumed they are the most commonly inherited.

### Other Types

There are rare instances in which other types of Quirks are developed.

One of those instances may manifest a Quirk that is entirely unrelated to their genetic lineage, akin to a mutation.

Another instance could be under special circumstances, where a second Quirk can be added to a person's genetics. Through this instance, multiple quirks can be taken and granted to others. There is also a chance that the two Quirks may merge from this process, becoming a new Quirk of its own, as was the case with One For All.