Quirk

A Quirk (個性) is a special power someone can possess in Boku no Hero Academia. These Quirks are split into multiple types.

History
The first Quirk was in a baby who was born in Quig Quig, China. It was born as a "Luminescent Baby". Over time, people started to get different kinds of Quirks, though no one knew why.

The Police Force, upholding leadership and protocol, decided not to include Quirk users in their ranks out of fear that people in the Police Force would use Quirks as weapons. After Quirks started appearing, everyone wanted to become superheroes; professional Quirk users who can fight people that use their Quirks for evil. Thus, the profession of superheroes (where people use Quirks responsibly) began in order to fill in the gap of crime fighting Quirk users.

It was stated that, "80% of the world population has a unique physical constitution" or has a Quirk.

Information
Quirks can be passed down by parents or can be a combination of both parents' Quirks. They can also run through a family as well.

Quirks were said to be the next step of evolution in the human race. The 20% of people who don't have Quirks have the last joint in their smallest toe because it was considered useless for bodily function, therefore those that do have the joint likely won't develop a Quirk.

Quirks typically manifest in children by the age of 4, however some are already born active with it, as is the case with Present Mic.

Although it is very rare, it is possible for animals to have Quirks too, as seen in Nedzu.

It is also possible for two Quirks to mutate and become a new Quirk, as seen with One For All.

Children in elementary school receive Quirk counseling. The goal is to make sure that the children don't get the idea that they can do whatever they want; this is done to prevent children from abusing their Quirks and becoming evil as a result, like Shigaraki.

According to Tooru, public display of quirks is against the law.

Known Quirk Classes

 * Emitter (発動 Hatsudō, lit. "Activation")
 * Transformation (変形 Henkei)
 * Mutant (異形 Igyō)