Highlights
Quirks are superhuman abilities found in 80% of the population in the My Hero Academia world, leading to the birth of heroes and villains.
Quirks tend to be mostly inherited, especially if they are dominant traits, and can emerge in children by the time they reach four years old.
Families play a crucial part in determining the nature of a person's quirk, whether it is an emitter, transformational, or mutant type. Quirks have the potential to mutate and grow more powerful as time goes on, which can instill a fear of losing control.
My Hero Academia owes its essence to quirks, without which the show would be unrecognizable to fans. This anime is built upon the foundation of superhuman abilities, possessed by approximately 80% of the population in the world of My Hero Academia. The emergence of quirks has given rise to heroes, individuals who utilize their powers for the greater good, as well as villains, who exploit their abilities for personal gain.
The origins of this enigmatic phenomenon remain largely shrouded in mystery. The only known clue points to a glowing infant in Qing Qing, yet beyond this solitary occurrence, little is understood. Quirks are hereditary, growing in strength and complexity with each passing generation.
The Genetics Of Quirks
Quirks have a strong hereditary component, with children having a high chance of inheriting a quirk if one or both of their parents possess one. The passing down of quirks is determined by dominant and recessive traits, with dominant traits having a higher likelihood of being passed on. However, if a quirk is recessive, it may not be inherited.
In most cases, passed down quirks manifest as single abilities or combinations. Occasionally, quirks can be double, as seen in the case of Todoroki who possesses both his father's fire quirk and his mother's icy quirk. It is uncommon for a child to not inherit a quirk, considering that over 80% of the population has quirks. This occurrence is rare and concerning. For example, the main character of My Hero Academia, Midoriya, was born without a quirk, which was determined to be a genetic anomaly.
Variation In Family Quirks
Children who possess a genetic anomaly known as a quirk typically exhibit their abilities around the age of four, although there are rare instances where manifestation occurs immediately upon birth. An intriguing indicator of whether a child possesses a quirk is the presence of an additional joint in their little toe. If this additional joint is absent, the child is deemed quirkless, whereas if only one joint exists, a quirk is present.
In the realm of quirks, family plays a vital role. One's lineage determines the nature of their quirk, which could originate from either the maternal or paternal side, or even manifest as a unique blend of both. Depending on the quirks present in their family tree, every individual with a quirk can be classified into three categories: emitter, transformation, or mutant.
Emitters possess the power to manipulate and influence their surroundings. Shigaraki is an example of an emitter, utilizing his decay abilities to annihilate people and objects in his vicinity. Eraserhead is also classified as an emitter, as he possesses the ability to temporarily nullify someone's quirk using his erasing power. Todoroki and Uraraka are among the other individuals with emitter capabilities. However, extended use of their powers causes these emitters to experience discomfort and pain.
Transformation is a unique and uncommon quirk category that demands focused concentration. Seiji Shishikura possesses this transformation ability. His quirk stands alone as the sole known transformation type that can change others into flesh-like forms. The permanence of this alteration allows for easy identification. Heroes with mutant quirks, such as Froppy, The Invisible Girl, Sero, and Iida, possess blatant physical differences. Froppy mirrors her frog quirk's appearance, while The Invisible Girl embodies her ability by being invisible at all times. Sero's body has been modified to accommodate his tape-shooting quirk, and Iida's calves possess exhaust pipes to support his engine-like ability. All these distinguishing characteristics can be attributed to their familial lineage.
The In-Universe Science Behind Quirk Mutations
The origin of quirks remains a mystery to both viewers and individuals in the world of My Hero Academia. Despite constant efforts by scientists to understand this sudden phenomenon, little to no progress has been made. Currently, it is known that quirks are inherited through dominant and recessive genetics. For example, Iida's family possesses the dominant gene for the engine quirk, resulting in permanent physical alterations to their bodies. On the other hand, Deku inherited his parents' recessive genes, leaving him without a quirk.
Some characters in the series display mutations in their quirks, leading fans to question why their abilities also have physical effects on their bodies. Quirks combine and evolve through generations, raising concerns that as long as this genetic inheritance continues and becomes stronger, they may eventually overpower humans.
The aforementioned phenomenon gave rise to the Quirk Singularity Theory, which posits that as quirks are inherited and merged, they undergo enhancement, complexity, and heightened potency. As time progresses, it is speculated that individuals possessing quirks will eventually lose control over them. Stream My Hero Academia on Crunchyroll.