Who is the strongest Esper in A Certain Magical Index

The Strongest Esper Power in A Certain Magical Index

Welcome class. A Certain Magical Index and its sister series A Certain Scientific Railgun are filled with super-powered individuals called espers. Esper is shorthand for a person with extra-sensory perception, the ability to use a so-called sixth sense. This sense is information gained outside of the standard set of senses a person has. In the case of the aforementioned series it includes people with a vast array of powers that can alter the physical world. Many of these powers make physics their plaything, so just who is the strongest esper in the A Certain Magical Index and A Certain Scientific Railgun?

Level 5's
Level 5’s

Remember I said the strongest power and not the strongest user, so for the sake of this discussion we can assume that all of them are at level 5 regardless of their actual standing. Also, I am limiting this list to people who have measurable powers related to physics, so no magic, or ultimate haxs.


The infamous Accelerator, first seen in A Certain Magical Index, has the ability to control the vectors of any object around him. A vector is anything that has magnitude and direction. An easy way to think of it is like this:
1- A car is moving 15 miles per hour- Not a vector
2- A car is moving 15 miles per hour due west- Vector
Just in case you were wondering this is an example of just how overpowered Accelerator is. (A Certain Magical Index season 2 epsiode 21)

We can do some simple math to get a rough estimate of just how much force accelerator is using when he threw the building.

Newtons second law

Force = mass x acceleration

A rough estimate for the mass of the building accelerator launched in the building would be 200,000,000 kilograms. A few more rough estimates can be used to determine the distance, speed, and acceleration of the throw.

Velocity of the building before impact = Distance / Time

V = 1000m / 6 seconds

V= 167m/s

Acceleration of the building = change in velocity / change in time

A = (167 – 0) / (1 – 0)

A = 167m/s/ 1 second

A = 167 m/s2

Force of the impact = mass of the building * acceleration of the building

F = 200,000,000kg * A = 167 m/s2

F = 33.4 x 109 newtons

For reference a Saturn V rocket which took mankind to the moon uses 35 x 107 newtons at liftoff. I guess academy city really doesn’t rockets to launch things into space since they can get Accelerator to just throw them into orbit.

So it might seem that Accelerator has the strongest power in A Certain Magical Index since he has basically made Newtons laws of motion his plaything. It is due to this power that he is nearly impossible to beat in a fight. One thing to keep in mind is that there are scalar properties. Scalar properties are things that have magnitude, but no direction. An example of a scalar property would be temperature.

Kakine Teitoku- Dark Matter

Kakine Teitoku, a villian from A Certain Magical Index, uses dark matter is not referencing the theoretical dark matter than astrophysicists discuss, but the ability to create matter that did not previously exist. Two of the main corner stones of physics would make this ability impossible under normal conditions. The law of conservation of matter, and the law of conservation of energy.
The law of conservation of matter states that matter cannot be created or destroyed, only changed into different forms.
The law of conservation of energy states that energy cannot be created or destroyed, only changed into different forms.
Despite this, it is not impossible to create new matter when you consider Albert Einstein’s famous theory of E = mc2 matter can be created using large amounts of energy. Let’s say for example Kakine wants to make 1 kg cannon ball to fire at accelerator.

E = energy

m = mass

c = speed of light

E = mc2

E = 1kg x (3×108 m/s)2

E = 1kg x 9×1016 m/s2

E = 9×1016 kg*m/s2 (newtons)

For reference the force of attraction between the Earth and Moon is 1×1020 Newtons
So Kakine has basically made the law of conservation of matter, the law of conservation of energy, and mass equivalence his plaything. Despite being able to make all sorts of new types of matter and energy, they would have a magnitude and direction when sent against Accelerator. As such they would have vectors and be susceptible to Accelerators powers. Kakine only chance would be to take out Academy cities number one esper early in the fight before Accelerator can learn to manipulate these new forms of matter and energy. This makes for a fun fight in the later light novels of A Certain Magical Index.

Mikoto Misaka- Railgun

The Railgun, who first appeared in A Certain Magical Index, has the ability to manipulate electromagnetism, which is one of the four key forces of nature. This force is based on the interaction between particles that have different charges, either positive or negative. These interactions create a variety of different effects including electricity and magnetism. This allows our favorite bug zapper to be a human taser, fire off lightening, attach to walls, and use her signature railgun.

A railgun is a weapon that uses electrical currents to create a magnetic field. The magnetic field then propels the projectile at high velocities towards the target. The advantage of a railgun over a conventional firearm is that it can attain much higher velocities. This allows for greater range and energy delivery to the target.

Realworld Railgun
Mikoto’s railgun

While Mikoto might be extremely effective against normal people, her abilities will create vectors, so she will be powerless against Accelerator, but she might have some success against Dark Matter. It would come down to her being able to take out Dark Matter before he can start to create a defense against her more powerful abilities.

FYI- I will revisit everyone’s favorite bug zapper at a later date once I brush up on some physics.

Mugino Shizuri- Meltdowner

It took some real doing to figure out just what is going on with Mugino and her powers given the lack of information given in A Certain Magical Index, and A Certain Scientific Railgun. However, I did manage to come up with a potential explanation using a lesser known (in terms of the general public) theory of quantum mechanics. Quantum electrodynamics deals with the interaction of matter and light, specifically electrons, and photons (particles of light). It allows them to calculate the following three things:

1- movement of photons

2- movement of electrons

3- emission of photons by electrons

With the ability to manipulate these three properties Mugino can create glowing balls of lights, electron beams, and lasers. She is also able to create a solid shield of electrons, but quantum electrodynamics cannot explain this ability. Thus, there are still some unknowns when discussing Meltdowners powers. Given the nature of her powers, they would be useless against Accelerator due to her powers creating vectors and Railgun due to the electrical nature of the electron beam attack which allows Railgun to deflect them. Dark matter would be a tossup and if she can create lasers she would have a chance against Railgun, due to lasers, being non electrical in nature.

Awatsuki Maaya- Float dial

While this power is normally held by Awatsuki a level 3 esper, for the purposes of this discussion we are going to raise her to a level five. Float dial is the ability to manipulate the buoyancy of an object and or the surroundings. Now I will admit that at lower levels of power it does not look all that impressive, but we need to take a closer look at how the power works before dismissing it.

Buoyancy is an upward force exerted on an object by the fluid it is currently located on. Please remember that fluids encompass far more than water and other liquids, so air is technically a fluid even if we do not commonly think of it as one.


While the above diagram does illustrate how buoyancy works, it does not help to actually calculate the buoyancy of the object. To do that we will need to use the formulas below:

Buoyancy = weight of the dispersed fluid

To calculate the weight of the dispersed fluid, and for the sake of time, we are going to skip a few steps.

(Density/ density of the fluid) = weight of the object / weight of the dispersed fluid

Now really quick for those of you who don’t know what density is, it is the amount of matter per unit of volume.

Density = mass/ volume

Thus the higher the density the more stuff that is packed into an area. If you look at the first diagram you can see that it is the density of the object and the density of the fluid that plays a large role in determining the buoyancy of an object in a particular situation. So what the Awatsuki is really doing is manipulating the density of the object.

Float Dial
Float Dial

There are two ways to change the density of an object: change its mass or change its volume. As we can see in the picture above the robot Awatsuki is holding is not any bigger or smaller, so what she is actually doing is changing its mass. Specifically, she is lowering the mass in order to be able to hold it over her head. In Universe she only seen raising buoyancy by lowering the density of the object by reducing the mass, because the volume of the object has not changed. Imagine if she was a level 5, she could theoretically begin to raise the mass of any object, changing its weight. Taken to the extreme she could use the increased mass and density to cause explosions via nuclear fusion, but the backlash to her would be rather extreme.

This is all well and good, but how would she rank against the other powers. Well, she could increase Accelerator’s mass, but it wouldn’t do any good as he can simply change gravity as it is a vector property, making her powers less effective on him. Dark Matter, Railgun, and Meltdowner have no direct defense against her powers, and Awatsuki lacks the range that the others have, so it would come down to who can use their powers in a more creative way. FYI- I do not think she has ever met Acelerator as she is no in A Certain Magical Index.

Kaitabi Hatsuya- Synchrotron

This particular power is stated to be the manipulation of quantum particles, and it does not appear in A Certain Magical Index, only in the sister series. These particles are in fact subatomic particles. These are the particles that make up the proton, neutron, and electron, which are the three particles that make up the atom. Over the past century 13 have been discovered and 3 more have been theorized to exist. The cannon material on the synchrotron power actually makes our job a bit easier as it is stated to be the manipulation of gravitrons.

Gravitrons are the theoretical particles that mediate the force of gravity; thus a synchrotron user could in essence manipulate the force of gravity. This would give the user a wide range of powers beyond simply making a person heavier or lighter, similar to the Float Dial. Additionally, he or she would be able to make a nuclear explosion by using gravity to compress matter to the point of inducing fusion. Unlike Float Dial, the synchrotron would be able to use gravity to protect himself or herself from the backlash of the explosion.

Sadly, still no take down of Accelerator due to his being able to reflect the radiation and energy released by any explosion synchrotron can release. He can also reverse the effects of any gravity manipulation placed on him. The only chance synchrotron has is to roast Accelerator using the temperature of the explosion. However, Accelerator could cancel out the explosion by trying to neutralize the gravity needed to make it. Dark Matter, Railgun, and Float Dial could make a shield against the explosion using their powers to absorb, or redirect the energy and radiation released by the explosion. They would still be vulnerable to the heat. Sadly, Meltdowner probably can’t do much of anything to stop it. The best case for everyone except Accelerator is to attack first, given the time it would take to set up the explosion, or before synchrotron can manipulate the gravity.

Uiharu Kazari- Thermal hand

Initially Uiharu is the weakest out of all of the powers on the list, but remember we are boosting her to a level five. Thermal hand is the ability to conserve the temperature of any object she touches as long as it doesn’t hurt her hand forcing her to let go. Temperature is the measure of the thermal energy, and particle kinetic energy of particles. On a basic level what temperature measures is how much a particle is moving and the higher the temperature the more the particle is moving. We can see this in the picture below.

states of matter
states of matter

Given the expansion of powers the other espers get as they level up we can assume that Uiharu will gain the ability to increase or decrease the temperature of objects and her surroundings. In essence she will make the laws of thermodynamics her toys. These laws deal with the energy in systems.

Laws of Thermodynamics

0- If two systems are each in thermal equilibrium with a third, they are also in thermal equilibrium with each other.

1- The internal energy of an isolated system is constant.

2- Heat cannot spontaneously flow from a colder location to a hotter location.

3- As a system approaches absolute zero, all processes cease and the entropy of the system approaches a minimum value.

Thermal hand lacks the ability to blow up a city block unlike many of the other powers on this list, but she is not defenseless. Imagine if you will Accelerator, Dark Matter, or Railgun launching a projectile at her but she is surrounded by a wall of heat that incinerates the projectile, before it hits her. Also this heat barrier would prevent them from being able to touch her. Meltdowner’s electron beams can be blocked if Uiharu creates a barrier at absolute zero a temperature so cold that the motion of all particles would stop and fall apart. This would cause the electron beam to fall apart. She has no defense against Float Dial and Synchrotron except for cooling the matter they might use to make explosions below the temperature needed for fusion.

I know it seems like she is fairly useless, as almost every other esper has a way to damage her in some way. Her one advantage is the ability to take down the so far untouchable Accelerator. She can take down Accelerator as temperature is a scalar property, which means he will be unable to defend against it. Her method of attack would be to increase or decrease the temperature around Accelerator until he is rendered unconscious. True Accelerator could manipulate vectors to stay warm or cool off, but these would become useless after a certain point as long as the temperature in the surrounding area continues to change.


Accelerator- beats everyone except Thermal Hand if he allows her powers to get up to speed

Dark Matter- beats everyone except Accelerator and Thermal hand if she can get the jump on him

Railgun- beats everyone except Accelerator and Dark Matter if she gets the drop on Dark Matter

Meltdowner- beats everyone except Accelerator, Railgun and Dark Matter if she gets a drop on Dark Matter

Float Dial– Loses to everyone except Thermal Hand

Synchrotron– loses to everyone except Thermal Hand

Thermal Hand- loses to everyone except Accelerator and Dark Matter as long as she has time for her powers to get up to speed.

I hope that you enjoyed this run through of some of the espers from A Certain Magical Index, and A Certain Scientific Railgun. If you have any comments or questions please leave them in the comments section below.

7 thoughts on “Who is the strongest Esper in A Certain Magical Index

  1. reyzakurrota says:

    But heat can’t affect accel since he completely unharmed in the middle of dust explosion. And he can walk normally in the sea of lava

    • Anime Science 101 says:

      All true, but I was looking at this from the stand point of playing the physics straight or at least as straight as a I can.

  2. SecretHope says:

    Nice material here 🙂
    Do next about real speed of railgun and the damage ot can do? 🙂
    Or maybe about Kuroko and her Teleporter or even what Level Upper do?

  3. Pingback: Five anime schools I would love to teach at - Anime Science 101

  4. Saksham Negi says:

    Heat is a scalar quantity but heat flux (flow of heat) is a vector one, so Uiharu is indeed not effective against Accelerator. It has been shown multiple times in anime too, he can control flow of heat thus deflecting heat away from him, he technically didn’t change the temperature but he pushed that away. Also temperature is just kinetic energy of atoms so if accelerator slows down the velocity of particles around him, he can ultimately reduce the temperature. Accelerator is truly the strongest at least in Academy City. And his awakened form wrecks some of the most powerful magicians too.

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