In My Hero Academia‘s world, 80% of the population is born with some supernatural ability. Quirks give the user various abilities, from breathing fire to transforming parts of their bodies. Since they are hereditary, an individual’s inherited ability typically depends on their parents’ abilities. Most offspring will inherit one, both, or some combination of their parents’ Quirks.
That said, MHA‘s Quirks have changed and evolved over time. They fall into four categories based on the nature of the ability and how the Quirk itself functions. These four types are emitter Quirks, mutation Quirks, transformation Quirks and accumulation-type Quirks.
Emitter Quirks, Also Known as Operative Quirks
Emitter Quirks take on various forms and are the most common Quirk type in My Hero Academia. This type of Quirk allows the user to generate, possibly control and/or alter their surroundings. Some emitter Quirks allow an individual to manifest materials such as water or fire, but take immense concentration to utilize.
Emitter Quirks can be manipulated at will or may require a prerequisite for the user to fulfill. For example, to activate his Brainwashing Quirk, Shinso Hitoshi must have his target answer him. In some instances, users with emitter Quirks can change the composition of surrounding materials on a molecular level, similar to Shigaraki Tomura’s Decay Quirk.
The nature of emitter Quirks is versatile and possesses many unique properties. Many characters in MHA have emitter Quirks, such as Todoroki Shoto’s Half-Hot Half-Cold, Aizawa Shota’s Erasure, and Uraraka Ochaco’s Zero Gravity. The user tends to suffer from severe drawbacks from over-using their Quirk, and it takes extensive training to minimize the repercussions.
Mutation Quirks, Also Known as Heteromorphic Quirks
My Hero Academia‘s mutation Quirks cause a permanent alteration to the user’s body. Since mutations are an aspect of the user, doing mundane tasks or blending in with society may prove difficult. Shoji Mezo’s Dupli-arms make it impossible for him to wear regular clothing. Spinner became an outcast due to his reptilian appearance and eventually fell into villainy. Interestingly, mutations are sometimes unrelated to the user’s Quirk at all. For example, Tokoyami Fumikage has a bird head, which does not correlate with Dark Shadow.
Compared to transformation or emitter Quirks, mutation Quirks can grant the user more complex abilities. These users can add to their already-present extremities or enhance preexisting abilities. Mutations cannot turn off, so users are not easily affected by erasure Quirks or drugs.
Transformation Quirks, Also Known as Composite Quirks
Transformation Quirks allow the user to temporarily alter their bodies. They can generate new body parts, change currently existing extremities, or even remove limbs altogether. Transformation Quirks can enhance the preexisting qualities of the user’s body. For example, Kirishima Eijiro’s Harden Quirk and Tetsutetsu’s Steel grant them the ability to increase their defensive stats by transforming and hardening their entire body.
However, the nature of transformation Quirks doesn’t give them the same versatility as emitter Quirks; most users have to rely on close-range combat. Additionally, this Quirk type can create multiple drawbacks. Transformation Quirks are temporary so if the character overuses their ability, their Quirks’ effects can wear off quickly.
MHA Also Has Accumulation-Type Quirks and Multi-Category Quirks
Sometimes, however, My Hero Academia‘s Quirks don’t necessarily fall into any of the three aforementioned categories. Accumulation-type Quirks, such as Fatgum’s fat absorption, require the storage of material. After storing fat, power or energy, users can unleash the accumulated substance and convert it into an attack. The drawback of this Quirk is that once the user exhausts all their stored power, they are rendered weak and defenseless.
In other instances, an individual’s Quirk can fall under more than one category. This often occurs when a character has a mutation-type Quirk in addition to a transformation or emitter Quirk. For example, Ashido Mina’s Acid Quirk is an emitter type. As a result, however, her skin is also pink. Genetics play a significant role in the Quirk inherited, so new combinations can form depending on what Quirk types the parents have. In even rarer cases, such as Eri’s rewind, the child can have a mutated gene which results in a Quirk that neither parent has.