Quirk Analysis

Himiko Toga

Izuku and Himiko, who is disguised as Ochaco

In this, we are looking at how Himiko Toga's quirk transforms even the clothes of the individual. With blood needed to complete the transformation, it seems that her quirk uses the DNA from the blood to complete the transformation, but the clothing they are wearing is not part of their DNA.

In the Provisional Hero License Exam, Himiko transforms into Ochaco Uraraka. Despite the fact that Himiko had taken the blood during their last interaction during the Vanguard Action Squad Invasion, Himiko's transformation into Ochaco is shown to be wearing Ochaco's hero costume, targets included. From this scene we can guess that although Himiko's quirk is fuelled by blood, it actually relies on either Himiko's memory and ability to picture the person she is transforming into, or her quirk detects and transforms her into the person's current form, clothing included.

Himiko transforming into Twice

Also in the Provisional Hero License Exam, Himiko copies Camie Utsushimi's appearance. However, with this transformation, Himiko drugged Camie before she ever changed into her hero costume but still changed in and out of Camie's appearance in her hero costume.

Similarly, in the Final War, Himiko copies Jin Bubaigawara's appearance despite the fact that the other is deceased, and her transformation shows no sign of injury or tear to the clothes, showing that Himiko's quirk doesn't copy a person's current appearance nor the last appearance they had, if the person is deceased.

Therefore, Himiko's quirk, Transform, must rely on her own mental image and ability to picture the person she is transforming into to work.

Neito Monoma

Neito drawing a 'blank' with Eri's quirk

Neito Monoma's quirk, Copy, draws a 'blank' whenever he tries to copy a quirk that is an Accumulation type quirk, like Izuku Midoriya's One For All or Eri's Rewind.

In Neito's words - "...Quirks function as stockpilers. I copy the core nature of the quirk itself. But if its an ability that accumulates something and changes it into a form of energy, I don't copy the stored-up fuel that would make it function."

However, as Neito improves his quirk and is able to hold onto and use copied quirks for longer periods of time, he will be able to build up his own stockpile for these quirks and be able to use it - for example, a quirk like Fa Jin or Shame has a short-term stockpile, which can be built up very quickly.

Another way Neito can get around quirk 'blanks' is by building up a stockpile before he copies a quirk. For example, if he built up a lot of body fat before he copied Taishiro Toyomitsu's Fat Absorption, when he did copy the quirk, it would make use of the fat already stored within his body. Similarly, Rikiya Yotsubashi's quirk, Stress, can have a stockpile built up before copying the quirk, as it only feeds off of the emotion the user has stored on their own.

Hitoshi Shinso

Hitoshi Shinso's quirk, Brainwashing, is not actually what it was named.

The name brainwashing implies that the user of the quirk is controlling the mind of whoever they use their quirk on. This is not what Hitoshi's quirk does.

A brainwashed Izuku

The limitations of Hitoshi's quirk include not being able to make his targets perform orders that do complex brain activity, such as writing down information from memory or following complex commands, and it can control a person's actions, but not their thoughts and feelings. Both of these limitations show that the quirk does not work on the target's brain.

Additionally, Hitoshi's quirk can be broken out of with a strong jolt or pain. As soon as any sudden stimulus occurs to the brainwashed individual, their mind is brought out of the fog it was put in and is able successfully fight the quirk for control once again.

But while Hitoshi's quirk does not control the brain of the individual, it is not completely a body control or puppeteering quirk either. The villain Dictator has a quirk called Despot, which draws many similarities to Brainwashing. But while Hitsohi's quirk is not a mind control quirk, by comparing Despot and Brainwashing, we can tell that it is not simply a body control quirk either.

The victims of Dictator's quirk are forced to move their bodies however Dictator tells them, like puppets. They, however, are still conscious in this state, and are able to think and talk freely.

So, Hitoshi's quirk can be classified as a type of body control quirk, with a minor hypnotic element - he can control the body of the target, but is not able to control the mind, only put it into a trance-like state, or thinking through a fog, so the person cannot fight back. He traps the mind inside of the person so that he can take control of their body instead.

Izuku Midoriya

Izuku Midoriya's quirk, One For All, is a combination of two quirks - Quirk Bestowal and an unnamed Power Stockpiling quirk.

One For All is transferred from user to user through the consumption of DNA, which would supposedly mean that the quirk transfers through rewriting the DNA of the recipient to wield One For All. But this may not be how it transfers.

The past OFA wielders

One For All's stockpiling ability is revealed to have been stockpiling the past users' quirks as well as energy, when the quirk hits a singularity point. This ability could be because of the quirk copying and storing the quirk genes of past users, but none of the quirks seem to alter Izuku's body in any way - he still has the extra toe joint indicative of a quirkless person, and his body has no minor mutations that quirk users normally have in order for their bodies to better handle their quirks.

But, if the stockpiling ability is capable of copying quirk DNA, it should be capable of copying other DNA as well, which would give Izuku the features of past One For All users, which does not happen. This means that the quirk must be stockpiling their quirks' essence through usage rather than DNA.

If the stockpiling quirk itself was capable of copying the Quirk Factor gene, then it would have copied the All For One quirk and any quirks he had when it was in All For One's possession. However, when One For All hits singularity there is no sign of this quirk being in Izuku's possession. This means that the stockpiling quirk only stockpiled energy before it was fused with Quirk Bestowal. Quirk Bestowal itself has the ability to pass on a quirk, and when it combined with stockpiling, it gained the ability to stockpile quirks, meaning whichever way Quirk Bestowal works to pass on quirk is how stockpile stores them - either through DNA or quirk usage.

New Order tearing apart Tomura's quirks

The stockpiling quirk can only stockpile energy and, upon being combined to form One For All, quirks. The past users' personalities are stored within the quirk for the same reason that All For One's stolen quirks still have the imprint of their original holder within them, and how New Order was able to fight back against Tomura Shigaraki - the quirk itself stores some imprint of it's user within itself.

Facts that suggest One For All alters a user's genetic code:

• Neito Monoma's copy quirk seems to rely on reading the DNA of an individual through skin contact, and then replicating the DNA within himself. When he tries to copy Izuku's quirk in the Joint Training Battle - Round Five, he registers Izuku's quirk as a 'blank' rather than as quirkless, meaning he can sense the quirk but cannot use it. However, arguing the opposite, you might say that Neito is unable to tell the difference between a 'blank' and a quirklessindividual.
• Shota Aizawa's erasure quirk works by blocking the expression of the quirk factor gene in an individual, and his power works on Izuku with One For All.

Facts that suggest One For All cannot alter a user's DNA:

• Izuku still has the extra toe joint
• Izuku doesn't have any of the extra modifications that come with a quirk to better equip the body for handling it, meaning he breaks his bones and causes great harm to himself while trying to control the quirk. Others like Shoto Todoroki and Katsuki Bakugo have mutation parts to their quirk that limit the harm they get from it unless they go over their own limits - Shoto has natural resistance to both hot and cold temperatures, and Katsuki is majorly immune to the heat and recoil from his explosions.
• It is unable to be stolen by All For One and cannot be transferred unless the user wills it. All For One steals quirks by transferring the quirk genes over to himself, rendering the victim quirkless. These quirk genes can be activated and deactivated by All For One, unlike many of the original holders of the quirk.

While this doesn't draw any indisputable conclusion, it does raise questions about One For All and even other Artificial Quirks. If One For All was indeed not able to alter a user's DNA, it would make the quirk immune to things such as the Quirk-Destroying Drug, Trigger or bioweapons like the Humarise's Trigger Bombs.

All For One and One For All

Spinner starts to suffer from the effects of holding multiple quirks

Normally, a person can only hold one quirk within their body. If another quirk is added, they can become mindless like the Nomu or Shuichi Iguchi after he was given the Body Bulk and Scalemail quirks. It can also shorten their lifespan, as the strain of having multiple quirks may prematurely age a person, like with Hikage Shinomori, the fourth user of One For All.

Unlike with these cases though, One For All and All For One don't seem to be under the same limitations.

Izuku Midoriya gained access to multiple quirks through One For All - these include Gearshift, Fa Jin, Danger Sense, Blackwhip, Smokescreen and Float. Similarly, All For One has gained possibly hundreds of quirks and is never shown to have any trouble wielding them.

The difference between these quirks and someone like Spinner is that they have quirks specifically designed to hold multiple quirks. Just like quirks come with built-in defences to minimize the damage a quirk does to its user, these quirks have built-in ways to house multiple quirks without harming the user.

The two most likely reasons is that their bodies have been modified to better hold the multiple quirks, or that the multiple quirks are held within the original quirk, therefore meaning that the user indeed only has one quirk.

All For One activating multiple mutation quirks

In the case of One For All, the second seems more likely - that the quirks are stored within One For All and not within the user.

However, with the All For One quirk, while it does seem that while the quirks are stored within his quirk, they remain deactivated in that state. For an example of this, All For One has multiple mutation quirks in his arsenal, and yet when they are not in use, or active, there is no trace of the mutations they cause. This means that when All For One activates a quirk to use, it is brought out of the All For One quirk's stockpile and into his body to be used. Because of this, his quirk has also modified his body to be able to handle the strain of multiple quirks.

Tomura's incomplete body unable to properly handle All For One.

In the case of Tomura Shigaraki though, who was actively harmed by the All For One quirk when it was in his possession and had to have his body artificially modified to handle the strain of multiple quirks, we can look at other cases of transferred quirks for an answer. Yuga Aoyama and Izuku Midoriya both had quirks that were transferred to them and these quirks harmed them when used, just like Shigaraki with All For One. While the original user of the quirks were not harmed when using their quirk, the quirk factor that modified the user's body to better handle the quirk is not always transferred over alongside the quirk. So, while these three characters have quirks, they do not possess any of the defences that mean the quirk does not hurt them.