To Aru Majutsu no Index is a series of light novels mainly set in Academy City, a technologically advanced academic city located at western Tokyo, which studies scientifically enhanced superhuman students who developed powers, known as ESPers. However, within this world of scientifically developed super abilities, there exists an underground world of magic and the occult connected to the religious institutions of the planet. Kamijou Touma, an unlucky boy who happens to be one of the many students within Academy City, possesses a mysterious power in his right hand known as the "Imagine Breaker", an ability which allows him to negate all forms of supernatural powers, whether they be magical or psychic. One day, he finds a young girl hanging on his balcony railing named Index. She is a nun from Necessarius, a secret magic branch of the Church of England, and her mind has been implanted with the Index Librorum Prohibitorum—103,000 forbidden magical books the Church has removed from circulation. His encounter with her leads him to meet others from the secret world of science and magic. Touma's unusual power places him at the center of conflicts relating magicians and science-based espers in Academy City. As Touma tries to help and protect his friends, he learns the people he knows are not as they appear and begins to attract the attention of magicians and espers alike as they try to unravel the secrets of Academy City and Index.
As the novels go on the focus of the story turns to the increasing hostilities between the Science Side, represented by Academy City, and the Magic Side, represented by the Roman Catholic Church, due to Kamijou Touma's actions putting a stop to several of their plans. Additionally, the story begins to follow two of Touma's former enemies: the Level 5 and #1 Esper Accelerator, who's on a quest for redemption trying to protect Last Order, one of the clones he used to slaughter in his former search for more power; and Hamazura Shiage, a Level 0 esper and former Skill-out leader who after being defeated by Touma became the lackey of ITEM, one of the many groups belonging to the Dark Side of Academy City.
The sequel series, To Aru Majutsu no Index New Testament, is set shortly after the end of World War III, the event the first series ended on. Kamijou Touma returns to Academy City, but he's not able to enjoy the peace he and others fought so hard to obtain. Instead, he and his allies have to prepare for the arrival of Gremlin, a group that threatens both the Magic and Science Sides, and their leader, the mysterious Magic God Othinus.
The first manga side-story, To Aru Kagaku no Railgun, focuses on Misaka Mikoto, an electromaster who is the third most powerful of the seven Level 5 espers in Academy City. Set before and during the events of the novels, the manga tells the adventures of Mikoto and her friends during that time period from their point of view. The Railgun manga ended up getting its own spinoff called Toaru Kagaku no Railgun Gaiden: Astral Buddy. This spinoff follows Junko Hokaze, a minor character in the manga and light novels that is a Level 4 esper, a Tokiwadai student and one of the main members of Shokuhou Misaki's clique.
The second manga side-story, To Aru Kagaku no Accelerator, focuses on Accelerator, the strongest Level 5 esper in Academy City. It's set shortly after he's shot in the head saving Last Order, when Estelle, a strange girl calling herself a magician, appears before Accelerator requesting his help, as DA, an organization belonging to the Dark Side of Academy City, is trying to use Last Order to further their goals.
Main Canon: The Light Novels (Original Toaru Majutsu no Index, New Testament and the various side-stories from Railgun and Index), Manga Spinoffs (Toaru Kagaku no Railgun, Toaru Kagaku no Accelerator and Toaru Kagaku no Railgun Gaiden: Astral Buddy), the Miracle of Endymion Movie and the Road to Endymion novel.
Secondary Canon: The adventure game Toaru Majutsu to Kagaku no Ensemble is likely canon in some level due to the aforementioned Road to Endymion novel being one of the four story routes in said game, the game explaining some details about the movie's plot and Kamachi being involved with the scenario writing and the creation of the game's original characters. The same can be said of the Railgun anime-only Poltergeist Arc, as the antagonist, one original character and the plot device introduced in it are canon to the main novels. However, the arc also has some inconsistencies with the plot and timeline of the manga and novels.
Non-canon: Crossovers, most video games, the Index manga, the Index and Railgun anime and the 4-koma spinoffs (Toaru no Nichijou no Index-san and Toaru Guuzou no Ippou Tsuukou-sama).
The verse as a whole is incredibly strong. The Science side has technology like advanced powered suits, orbital satellite lasers with more power than a nuke, fighter jets that can fly at Mach 6 and if given enough time have the ability to split apart continents and gravity technology that could be used to compress the earth and to the size of a fist. They also have espers with wildly various levels of power, from low level telepaths to espers capable of facing and defeating an entire army and severely damaging entire cities. The arguably more powerful magic side has magical beings such as Archangels capable of manipulating celestial bodies, Magic Gods capable of manipulating probability and casual reality warping on an universal scale, magical weapons capable of nuking cities, and some world ending weapons that can devastate the entire planet, as well as Saints, who are often compared to nuclear bombs because of their power.
As stated above, the verse is very strong. The universal reality warpers, angels, several esoteric abilities and various hax put the series at a relatively high level of power. HOWEVER, many characters are glass cannons as fragile as normal humans, while others lack the speed needed to keep up with characters from faster universes.
Note: Several characters, particularly magicians belonging to the Magic Side, but also some espers from the Science Side, owe their superior Durabilities to their magic/esper power. Thus, they are vulnerable to opponents who wield a sufficiently powerful form of anti-magic or anti-psychic power, like the main character Kamijou Touma and his Imagine Breaker.
Magician: A magician (魔術師 Majutsu-shi lit. Magic User) is a person trained to use magic. While any human being can use magic as long as they follow the proper steps and precautions, magicians are extensively trained and suffer less risks if something goes wrong during the process.
Magic: Magic is a complex system of arts, disciplines, and traditions beyond the knowledge of science that allows its users to manipulate and distort the world around them. Unlike esper powers, magic usually requires some sort of previous preparation; be it the making of a temple and a ritual or the construction of a Spiritual Item or Symbolic Weapon. However, unlike espers, which are restricted to one power, a magician can wield several types of magic. There's two broad categories of magic: Idol Theory or Imitative Magic, in which an imitation of a whole or parts of a subject, the source, gains properties and attributes that are inherent to that source (which could be an item, weapon or story), e.g: a replica of a magic sword gaining properties of the original; and Infection Magic, in which parts of a subject (items or even beings) are used to remotely affect or attack it, e.g: an effigy used to attack a person through one of their hairs.
Mana: Mana is the energy that allows magicians to cast magic, and is present in all forms of life. There's also natural mana sources that some magicians and Spiritual Items may use in the form of ley lines. One way of using mana is through the refinement of the user's inner lifeforce, similar as to how crude oil is refined into other substances. As the source of mana is one's lifeforce there's a limit as to how much mana a magician can produce. Once this limit is reached their own body will refuse to continue the process out of self-preservation. Similarly, it's speculated that immortal beings like the mythical vampires might possess unlimited mana due to their inexhaustible lifeforce. Due to their training magicians have larger amounts of mana than the average person, which allows them to tell if someone is a magic user just by standing close to them. Additionally, each discipline of magic (Norse, Shinto, Christian, Hindu, etc) requires different kinds of mana, which sometimes allows experienced magicians to perceive which discipline a spell or spiritual item belongs to.
Telesma: Telesma is the power dwelling in the Phase known as Heaven and the source power for Angels. Some items or magicians use Telesma to achieve great power, since the potency of Telesma can't be compared to normal mana. The human body cannot handle a large amount of telesma due to a difference of affinity, not a matter of potency. If a human does forcefully absorb a large amount of Telesma it will result in harmful effects in their body.
Spiritual Item/Symbolic Weapon: A special tool prepared by the magician in advance to cast magic more efficiently and conveniently, normally using Idol Theory to grant the item/weapon power. As long as the item in question is similar in shape or function it will gain some of the original's properties, like an umbrella with a knife on the end standing in for a spear, but it will obviously gain less than a more faithful replica would receive. There's some items, especially those of divine origin like the Longinus Spear, the Holy Grail or divine weapons, that can't be accurately replicated through normal human techniques.
Saint: Saints are a powerful and rare existence in the Magic Side, with less than 20 of them existing in the world. Their power is based on Idol Theory: Humans are said to be made in the image of God, and Saints are said to be a higher replica that can bring out more strength, having a body which is closer to the Son of God due to being naturally born with God's blessing. Traits that most Saints have include superhuman physical strength, incredible speed, the capacity to channel a larger amount of mana compared to normal magicians and superhuman senses (for example Kanzaki Kaori has 8.0 visual acuity and can easily tell people apart at 600m, while Acqua of the Back can easily hear a whisper at 10m). They are also blessed with success and have naturally high luck. For example, Kanzaki was stated to be able to easily win over people's hearts without trying and has survived multiple assassination attempts through pure luck, such as a bullet deviating mid-path for no reason or a bomb exploding right next to her and failing to even scratch her. However, their same unique traits also make them more vulnerable to attacks that resemble how the Son of God was killed (being stabbed, a crown of Thorns, and the crucifix), though this weakness normally is inconsequential since most magicians don't have the power to exploit these weaknesses, and most Saints are aware of this problem and take measures to avoid being affected. Due to their power, Saints are capable of taking down an entire city or magical organization on their own, and they are considered comparable to nuclear weapons in terms of their importance in the Magic Side.
Magic God: Magic God (魔神 Majin) is the term used to refer to a magician that has mastered magic to the point of being able to bend all things in the world without exception through magic, becoming a being that transcends normal magic and steps into the realm of God. As such all possibilities are open for their power, like turning the sky green, resurrecting people, making 2+2 equal 5, controlling time or even destroying the universe. But that produces an omnipotence paradox, because all possibilities also include negative possibilities like losing against a child in a game of rock-paper-scissors. This paradox normally restrains a Magic God's power to work only 50% of the time, but a Magic God can eventually overcome this weakness. A Magic God's knowledge of magic is so great they are likely to be able to copy any spell they see being used, even if it's just once. The process of becoming a Magic God has not been described in detail and it seems to differ from Magic God to Magic God, but from the ones who have appeared in the series it seems to require a ritual of some kind.
Phase: A Phase is a layer applied over the world, in this context referring to the entire universe or reality itself, which acts like a veil or filter, and changes how the world appears to be. Several layers exist in the world, with many of them having been created by religions through unknown means. The known phases in the world include Heaven, Hell, the Underworld, the Pure Land, Yomi, the Abyss, Olympus, the Fairy Island, Nirai Kanai, Asgard, the First Sun, Takama-ga-hara and Amaravati. Beyond all filters there's a world of science untouched by religion or magic, referred to as the Pure World. Magic Gods have been shown to be capable of warping reality as they see fit by creating, erasing or manipulating these Phases. Some weaker magicians and magic items are also able to affect Phases in some way.
Original Grimoire: A grimoire is a book containing esoteric knowledge about magic and powerful spells. Only a few experts can read grimoires, as the knowledge inside a true grimoire is of a different world, and contradicts common sense, a knowledge that is far too alien to be safely comprehensible by any normal human, whose minds and bodies will suffer from its "toxin" if they try to read it. That "toxin" is the result of the reader’s mind rejecting such a great discrepancy from their common knowledge and wisdom. Even those few experts are threatened by grimoires, as the knowledge that a grimoire possesses is "poisonous" in the sense that it is too "pure" for the human mind to handle and must be "watered down" - i.e. written in such a way that many of its meanings are obscured—in order for people to be able to read it without their minds being destroyed or being led into insanity, plus a variety of other harmful effects. Grimoires are practically "eternal" in the sense that they cannot be destroyed with current human methods (such as burning them) and can only be sealed away, as they use ambient magic like leylines to protect themselves. Grimoires possess some degree of sentiency, as they desire and act to spread the knowledge they contain to people, and may even turn against their users if they feel that they are threatening their chances of spreading their contents.
Esper: Esper (能力者 Nōryokusha, lit. Ability User) is a term used to refer to a person who emits AIM. It's generally used to refer to people who have gone through Academy City's Power Curriculum Program and artificially gained an ability, though natural espers called Gemstones also exist. Unlike magicians, espers only have a single power, but they usually do not need any previous preparations to use it. Additionally, despite only having one power many espers come up with several aplications for it. Esper powers are clasified into two groups: Psychokinesis, which lists all powers that allow the user to physically influence the world around them, e.g: Telekinesis or Pyrokinesis; and Extra Sensory Perception, which lists all powers that involve the reception of information not gained through the recognized physical senses but instead use supernatural senses, e.g: Clairvoyance or Thoughtography.
AIM: An Involuntary Movement, better known as AIM, is a term used to refer to the phenomenon in which an esper involuntarily produces a weak invisible energy around themselves, while the AIM Diffusion Field is the energy field that surrounds the esper that is made up of the aggregation of that energy. The AIM Diffusion Field affects the esper's surroundings in microscopic ways depending on their power. For example, pyrokinetics heat up their surroundings, telekinetics create pressure, and electromasters release electromagnetic fields. The AIM Diffusion Field is normally only detectable through the use of machines, and is unique to each esper.
Personal Reality: Personal Reality is the source from which all esper powers and phenomena are brought into the real world. It's the esper's distorted personal vision of the world, thus being unique to each individual and irrevocably linked to their ability. It allows the user to utterly ignore the Uncertainty Principle, and with regards to the Schrödinger's cat thought experiment, would allow them to choose the possibility they want, or more specifically, distort a micro world using different laws, or more accurately, control their microscopic observations of the world and use them to cause effects on a macroscopic scale.
Level: Espers in Academy City are classified in a Level system depending on the strength of their powers. The system goes from Level 0 (Person with No Powers, any power they have is too weak to be of any use or they are unable to consciously control it) to Level 5 (Person with Super Powers, powers of an extent that their wielder can fight alone against a military force on equal or superior terms). A Level 6 (Person with Absolute Powers, the user is considered to surpass humanity and enter the realm of God) has been theorized to be possible, but so far nobody has been able to reach it.
Magician-Esper hybrid: While it's true that anyone can learn how to perform magic, espers are usually prevented and advised against doing so. Several collaboration experiments between Academy City and the Magical Side have proven that any esper that uses magic will suffer severe damage, as the two power formats are incompatible. The body part that is damaged is seemingly random, and as such one esper could be able to cast magic a few times without any fatal damage or immediately have their heart or brain severely damaged by their first spell, something that has drawn comparisons to playing Russian Roulette. The only successful magician-esper hybrid is Tsuchimikado Motoharu, as his esper power repairs the damage his body suffers with each spell. However, even his ability to recover is limited and could fail at any moment, so he only uses magic when there's no other choice left.
People-Clearing Field: A People-Clearing Field is a special field created by magic, used to keep people away from a certain area. They are commonly used by magicians to conceal their activities from unrelated people. The field interferes with the unconscious in order to divert the attention of unrelated people and prevent their intrusion, up to a certain level. Operating on a principle similar to Feng shui, it alters the natural flow of power in a location, creating areas of "comfortableness" and "uncomfortableness", in order to influence the flow of people away from the target area. There's a limit as to how much disturbance the field can conceal, and if the field's capacity is surpassed it'll be neutralized. Most magicians can be assumed to know this spell.
St. Peter's Interception Spell: St. Peter's Interception Spell, also known as the anti-flight spell, is a widespread spell that has restricted the use of flight by magicians. The spell is derived from a story involving St. Peter, one of the Twelve Apostles, confronting a magician called Simon Magus. When Simon flew freely through the sky, Peter said "Oh, demons carrying this magic user, promptly let go!!", causing Simon to lose the ability to fly and fall to his death. The spell is casted by saying the same phrase, after which magical flight will be neutralized and the flyer will be cast down to the ground. Variations of the spell have different effects besides reducing the flyer's altitude to zero, like an additional prevention of the flyer to initiate flight again. It appears to require the flyer to be at a minimum altitude to work, as it has been said that in theory a magician would be safe up to 10 meters. This spell has spread far and wide due to being simple yet powerful and effective, as well as being based on a famous story, so most magicians can be assumed to know this spell.
Flight: It's been stated that modern magicians can easily achieve flight through a variety of spells. However, the popularity and effectiveness of the aforementioned anti-flight spell has basically prohibited the use of these spells to almost all magicians. While not many magicians have been shown using this kind of spell due to this limitation, it has been implied a few times in the series than any good magician would be able to put together a flying spell if the situation required it (for example, Kanzaki and Stiyl are stated/implied to be capable of doing so, and all witches can easily achieve magical flight through the use of a magic potion and a broom). It can be assumed that most magicians can gain the ability to fly if given an unknown amount of prep time, likely depending on the magician's skill.
Curse Countermeasures: It has been said that any decent magician can sense the signs of simple curses like the Ushi no Koku Mairi and put together countermeasures against them, for example carrying a doll to take their place as target or escaping into a magic circle drawn into the ground to divert the curse's aim. It can be assumed that most magicians possess the ability to counter and protect themselves from curses, with the effectiveness likely depending on the curse's strength and the magician's skill.
The following is a general representation of in-universe power levels for people unfamiliar with the series. A full tier list would probably be too extensive due to the large amount of characters of the verse, so only the most notable will be listed.
- God Tier: True Gremlin Magic Gods, 100% Othinus, Aiwass.
- Top Tier: Ollerus, Fiamma of the Right, Archangel Gabriel, nerfed True Gremlin Magic Gods.
- High Tier: Accelerator, Kakine Teitoku, Fuze Kazakiri, Carissa, Elizard, Maiden of Versailles, Saints, Knight Leader, Misha Kreutzev, Thor with Mjölnir support, Mjölnir, Level 6 Shift Mikoto, Leivinia Birdway, Rensa. Possibly Sogiita Gunha.
- Middle Tier: John's Pen Mode Index, Mikoto Misaka, Shizuri Mugino, AIM Burst, Aureolus Izzard, Vento of the Front, Terra of the Left, Thor, Salome, Level 4 Espers, skilled magicians, strong Academy City weapons.
- Low Tier: Low-level Espers (1-3), regular magicians, Level 0s, fighters without supernatural powers, weaker Academy City weapons.
- Joker Tier: Kamijou Touma, 50/50 Othinus, Kamisato Kakeru, Shokuhou Misaki, Aleister Crowley.
Notes: The names in each tier are not necessarily in order of strength. It's important to consider that there's a gap of power between the high and top tiers, and a HUGE gap between top and god tiers. The Low and Middle tiers are close enough that a weaker character might be able to reliably pull out a win due to good compatibility, exploiting a weak point, smarts, etc... The Joker tier lists those characters whose powers make them able to challenge and beat much stronger characters, but might be beaten by weaker characters due to some conditions on their power/s.
- Devil slayer99
- Yomi Schwarz
Level 5 Espers
Level 4 Espers
- Shirai Kuroko
- Musujime Awaki
- Junko Hokaze
- Kouzaku Mitori
- Kongou Mitsuko
- Misaka Worst
- Kinuhata Saiai
- Kuroyoru Umidori
- Iruka Yumiya
- Yobou Banka
- Shutaura Sequenzia
Level 0 Espers
- Kazari Uiharu
- Girl in the dress
- Kumokawa Seria
- Wannai Kinuho
- Awatsuki Maaya
- Kumokawa Maria
- Frenda Seivelun
- Mitsuari Ayu
- Silvercross Alpha
- Ayame Fusou
- Shoubu Yamashiro
- Arei Houjou
- Bisai Otome
- Kihara Amata
- Kihara Gensei
- Therestina Kihara Lifeline
- Kihara Ransuu
- Kihara Enshuu
- Kihara Byouri
- Kihara Noukan
- Kihara Yuiitsu
- Kihara Nayuta
Angels of Science
- Anti-barrier revolver shotgun
- Metal Eater
- Random Number Ultrasonic Blade
- HsPS-15 "Large Weapon"
- High Speed Powered Suit
- HsAFH-11 "Six Wings"
- Enemy Blaster
- Bee Launcher
- Highway Cheetah
- HsSSV-01 "Dragon Rider"
- FIVE_Over Modelcase_"RAILGUN"
- FIVE Over OS Modelcase "MENTAL OUT"
- Power Lifter
- Anti-Art Attachment
- Processor Suit
- Prototype Coffin
- Qiong Qi
- Type-series Robot
- War Armadillo
- Large Mobile Weapon
United Kingdom and Necessarius
- Lola Stuart
- Sherry Cromwell
- Tatemiya Saiji
- Amakusa-Style Remix Church
- Knights of England
- Marie Spearhead
- Mallybath Blackball
- Jane Elves
- Theodosia Electra
- Richard Brave
- Freadia Strikers
- Cynthia Exment
- Víðarr Shoes Woman
- Orsola Aquinas
- Qliphah Puzzle 545
Roman Catholic Church
True Magic Gods
- Mark Space
- Yamisaka Ouma
- Oriana Thomson
- Sasha Kreutzev
- Krans R. Tsarskiy
- Hitokawa Hasami
- Emilie Fordia
- Wyss Winered
- Ureapaddy Exica
- Samuel Liddell MacGregor Mathers
- Mimetic Predator