The second arc of A Certain Magical Index, consisting of volume 2 of the light novels and episodes 7-9 of the anime. This story arc was omitted from the manga for some reason, even through some important plot points happen here.
Roughly two weeks after Index was saved, Stiyl Magnus returns to Academy City and enters a place called the Windowless Building to meet Academy City's ruler, Aleister Crowley. This mysterious figure floats upside down in a glass tube full of fluid, apparently a life support system. Stiyl explains that a rogue magician has kidnapped someone with the power Deep Blood, the power to kill vampires, and is hiding in Academy City's Misawa Cram School. To protect the fragile truce between the Science and Magic Sides, Stiyl will be allowed to deal with the magician in his own way, but Academy City's forces will not interfere. However, Aleister grants Stiyl permission to recruit Touma Kamijou to assist him. Stiyl is surprised, and Aleister claims that it will be all right. Touma is a loser who does not know and cannot leak any of Academy City's secrets, plus he cannot perform magic and is not intelligent enough to teach anybody else about it, so he will not leak any of the Magic Side's secrets. Stiyl muses in his head that Aleister surely knows all about Imagine Breaker, so why is Touma considered so low when he has one of the most dangerous weapons of all time? As he starts to leave, Aleister asks him to ponder a philosophical question: Deep Blood proves the existence of vampires, so what existence does Imagine Breaker prove?
Touma's apartment was repaired, so he and Index go back to living in it. Touma lives life as he did before, keeping his memory loss a secret from everyone. He literally has no memories from before he woke up in the hospital, but Heaven Canceler had filled him in on certain details and he is able to fool his classmates and teacher. He gets annoyed that Index eats so much, as he has very little money. She continues wearing her nun's habit in public, despite the stares it brings from everyone. One day, while they prepare to eat out, they run into Pierce Aogami and Motoharu Tsuchimikado. The two congratulate him on going on a date with such a hot foreigner who speaks perfect Japanese (Index is from England), which annoys him, but then Pierce angers her by commenting on her flat chest. Nonetheless, the four of them go to a fast food joint. On the next table is a girl dressed as a Miko. Curious, they talk to her, and she asks for help because she used up all her money after she ordered and ate thirty burgers. They are all shocked since she still looks slim, but Touma makes fun of her for not spending wisely. The others scold him and tell him to give her some money, but the girl asks all of them to give her money, especially Pierce, who called her beautiful and took some photos of her. Index comments on how shameful it is that a miko would resort to "selling her face", but the girl retorts that she's not actually a miko, she's a magician. Index calls her a liar and reveals some magical terms that the girl doesn't understand, proving she isn't a magician, while Touma and his friends look on bemused. Suddenly, some men in suits walk up and say they are there to take the girl home. She leaves with them, explaining that they are employees of the cram school she goes to. After they leave, Pierce suddenly wonders why employees of a cram school would bother checking up on a student after hours.After their meal, they go their separate ways. While walking home, Index spots a stray cat and asks if they can keep her. Touma refuses, saying his landlord doesn't allow pets, but she is adamant and has already named it Sphynx. Sphynx runs off and Index starts to chase her, but she says she can detect a flow of mana and runs in another direction. Stiyl walks up to Touma, saying he created another people-clearing field so they can talk freely. Touma doesn't recognize him, but plays along. Stiyl suddenly attacks him with fire, but Touma blocks and extinguishes it with Imagine Breaker. Stiyl is pleased that Touma is on his toes. He shows him some files and gets down to business. A rogue magician named Aureolus Izzard, who specialized in alchemy, snuck into Academy City and took over Misawa Cram School, apparently brainwashing everybody inside. He is holding someone with the power Deep Blood prisoner. Stiyl's colleagues theorize that Aureolus' plan is to capture a vampire and use it to gain immortality, since Deep Blood can find vampires as well as kill them. Stiyl wants Touma to help him enter the school, rescue the prisoner, and apprehend Aureolus. If Touma refuses, he will take Index away. Stiyl says Deep Blood's name is Aisa Himegami and shows a picture of her. She is the girl in the miko outfit from earlier. Touma agrees to help.In a flashback, Himegami wandered through an empty village, surrounded by piles of ash. She sadly remarked that she killed them all, meaning they were all vampires, as vampires turn to ash when they die.Touma goes to his apartment to tell Index he'll probably be gone all night. He finds that she snuck Sphynx inside and gets annoyed, but she promises to take good care of her. He warns her not to let the landlord see the cat and meets Stiyl outside. Stiyl sets up several rune cards outside, explaining that Innocentius will automatically be summoned if anyone tries to attack Index while they are gone. Touma dryly comments that Stiyl is obviously in love with Index. Stiyl starts blushing and stammering that he is doing this to be professional, but Touma doesn't buy it.As they walk to Misawa Cram School, Touma asks about Aureolus' abilities. Stiyl says that he was known for experimenting with alchemy and had been mocked for it, as even the Magic Side thinks alchemy is just a scam. However, he is not to be underestimated, since he has written and proofread many magical texts and has vast magical knowledge.They enter the school and find that nobody inside can see or hear them. Stiyl explains that Aureolus has set up a variation of the people-clearing field. Leaning against a wall is a man in a suit of armor, in a pool of his own blood. In the anime version, he is already dead, but in the light novel version, Touma and Stiyl give him some comfort before he dies. Stiyl recognizes the man as a member of The Thirteen Knights of the Roman Catholic Church, who apparently tried to apprehend Aureolus himself, only to be crushed and left to die, invisible and inaudible to the students. Touma tries to dispel the field with Imagine Breaker, but can't, and Stiyl explains that just like with Innocentius, the field instantly regenerates, so all they can do is find Aureolus and defeat him. Out of curiosity, Touma uses his cellphone to call his apartment. It works and Index answers, though she is very ignorant about modern technology. Stiyl comments with slight jealousy that many people had been Index's companion besides them, and Touma was merely the only one who managed to save her. Touma sadly muses in his head that the one who saved Index was killed when his memories were erased, and all that is left is him.The two wander through the building and enter the cafeteria. Suddenly, the field disappears and the students all glare at them. Stiyl says Aureolus is on to them and the students are all under his control. The students all start chanting spells and firing energy blasts at them while charging. Touma runs away. Stiyl follows him and calls him a coward, asking why he's not blocking their attacks with his right hand. Touma calls him a moron for not noticing there's over eighty students; he can't block them all with just one hand. Suddenly, Stiyl pushes Touma down the stairs. The students follow Touma and don't see Stiyl, who runs off. Touma realizes Stiyl used him as a decoy and says he will pay for that.Touma finds himself alone with one of the brainwashed girls. He finds that she is bleeding profusely and it worsens every time she uses a spell. He is horrified to realize that this is what happens when an esper tries to use magic. He tries to get her to stop, but she doesn't and eventually collapses. Himegami walks up and says she will help him treat her.Stiyl sees several of the students have collapsed from their magic-induced injuries and is disgusted. Aureolus walks up and attacks him with a dart attached to a chain that he can use to retrieve the dart. Anything the dart pierces immediately turns to gold. He calls this spell Limen Magna. Stiyl dodges the dart by using his control over heat to make mirages. He also deduces that this enemy is not the real Aureolus Izzard, but a homunculus in his shape. Enraged, the Aureolus Dummy attacks again, but Stiyl summons his Flaming Sword and chops off his left hand and left leg. The Aureolus Dummy stabs the surroundings with the dart and converts them into molten gold. He then escapes while Stiyl is busy dodging the boiling stream.Himegami and Touma patch up the girl. She comments that since her ability has to do with blood, she is a bit of an expert on it. The girl's capillaries are what burst, so she should be okay as long as her injuries are sterilized and healed. Himegami then claims she is a magician, and pulls out her "wand", but it is an electric police baton. He tells her to quit messing around, and they should get out of here. She asks what he means, and he says he and Stiyl came to rescue her. Surprised, she asks why, and he says it was the right thing to do, and he doesn't need a reason to save someone. She blushes, but the Aureolus Dummy arrives, having formed a golden Hook Hand and golden peg leg to replace his lost appendages. To their horror, he demonstrates his Limen Magna on the surroundings, then attacks them. Touma tries to catch the dart with his right hand, but his palm gets stabbed. To the Dummy's shock, Touma doesn't turn to gold and the dart and chain disintegrates. Aureolus Dummy reveals he can recreate his weapon and attacks again. Touma repeatedly destroys it with Imagine Breaker. Suddenly, the dart goes past him and straight at Himegami. At the last second, the girl they treated wakes up and uses herself as a shield. Grief-stricken, Himegami tries to go to her, but the girl smiles, turns to gold, then melts. Touma gives a scream of pure rage.Aureolus Dummy attacks again, but Touma catches the chain with his left hand. He then beats the shit out of him, even using the chain to whip and strangle him. When his begs for his life, Touma snaps out of his rage and releases him. As the Dummy crawls away, Touma sadly muses that despite everything his opponent had done, he couldn't bring himself to kill him. Aureolus Dummy crawls slowly dying, since Imagine Breaker destroyed his internal power source, but feels an odd satisfaction. He had been pondering a philosophical question about whether a man can gain ultimate power and retain his humanity, and believes Touma has given him the answer, as he remained human despite having the power to destroy magic. Stiyl approaches him and asks if he was the one who wounded the knight at the entrance, but he says no. Satisfied, Stiyl gives his magic name: Fortis931 - I Prove Why My Name Is The Strongest Here. The Dummy reveals Aureolus Izzard's magic name: Honos628 - My Honor Is For The World. There is nothing that can be done to save Aureolus Dummy, so Stiyl ends his pain by incinerating him. He starts searching the building again, but is confronted by the real Aureolus...Note: In the anime, the entire subplot with Aureolus Dummy is omitted. Instead, the real Aureolus appears right away.Meanwhile, Index takes a bath with Sphynx. She gets dressed and decides she wants to see Touma. She steps outside and finds the rune cards Stiyl left. Suspicious, she traces their mana signature and runs toward Misawa Cram School.Touma tries to convince Himegami to leave with him, but she says she is not a prisoner, pointing out that she had been allowed to leave for short periods. She explains that she has no control over her power. Vampires are attracted to her blood and rush to drink it. However, once they do, they automatically die. Even when other vampires see this, her blood's allure is too great for them to overcome. She says vampires are just like ordinary people and many of them are good, so she regrets being born with Deep Blood. One day, Aureolus found her and offered her a deal. His plans require a vampire, so if she can attract one, he can capture it. Then, he will rid her of her power. Touma says even if he was telling the truth, what he's doing to the students is inexcusable. Their conversation is cut short when the real Aureolus appears. He says, "I will come to you now." and then he's suddenly right next to them. He says he is here to reclaim Himegami. Touma gets enraged that he's talking about her as if she were property and tries to attack him. Aureolus says, "You shall not touch me." and Touma is shocked to find himself running in place like he were on a treadmill. The alchemist pulls out a metal acupuncture needle, but Himegami stands between them. She says if he kills Touma, she will kill herself. Aureolus agrees not to kill him. He stabs himself in the neck with the needle, then tells Touma, "Forget everything."Touma and Stiyl wake up in a playground somewhere, with no memory of how they got there and what they were doing. However, when Touma touches his head with his right hand, the memories Aureolus erased come back. He tells Stiyl to stick out his tongue. Confused, he complies, and Touma uppercuts him, simultaneously restoring his memories and making him bite his own tongue, with Touma saying that's payback for using him as bait and abandoning him earlier. They rush back to the school.Index enters Misawa Cram School. Aureolus happily greets her. She doesn't know who he is, but he says that's to be expected. He tells her to sleep, and she falls unconscious.
Touma and Stiyl arrive at the building to find it surrounded by the remaining Knights of the Roman Catholic Church. The Knights chant a spell and cause lightning to strike the building and make it collapse. To everyone's horror, the building suddenly repairs itself, like a demolition recording being played in reverse. Then, a magical blast issues that annihilates the Knights. As they stare at the building stupefied, Touma suddenly notices Sphynx carrying Index's hood. Aureolus carries Index into his office and lays her on his desk, with Himegami by his side.Stiyl says he's figured out what is going on. He reveals that Aureolus used to be Index's partner, like he had once been and Touma is now. Three years ago, he tried and failed to save Index from having to have her memories erased, and was so devastated that he ran off and hid in seclusion. He's apparently used his time in hiding to develop his strange ability and come up with a new plan to save her. The problem is that since he has had no contact with the outside world, he doesn't know that she has already been saved.They enter the office. Aureolus asks them why they are interfering, since they care for Index as well and want her to be saved. He monologues his plan. First, he had to acquire the ultimate alchemy, Ars Magna, the power to alter reality. According to the legends, it can only be achieved by continuously chanting for 120 years, but he brainwashed the students of Misawa Cram School to chant simultaneously, cutting the time down to about three years. The fact that the students were suffering because they were espers meant nothing to him, as he would simply fix them with healing spells so they could start all over again. In the anime, he doesn't explain how he gained Ars Magna. Next, he'll use Himegami's Deep Blood to attract a vampire and then he will capture it with Ars Magna. Vampires all have Photographic Memory and live forever without any problems, so he will force it to reveal how Index can live without overloading her brain. If humans cannot use the method, then he'll force the vampire to turn her. Everybody is disgusted, but he says if it comes to that, at least she will be saved, and immortal to boot.Stiyl apologizes and tells him the awful truth, Touma had already saved her. Stiyl briefly explains Imagine Breaker and how Touma used it to break the curse that was causing her to suffer every year. Aureolus is shocked that all his effort was for nothing. Index briefly starts sleep-talking, calling for Touma and asking for food. Overcome with rage and jealousy, Aureolus yells, "Slam to the ground, intruders!" Touma and Stiyl fall on their stomachs, unable to move. The alchemist says they will pay for trampling his dreams and stabs himself in the neck with another needle, but Himegami begs him to stop. Touma finds that he can still move his right arm, barely, and desperately inches his right hand toward his face. Annoyed, Aureolus tells her, "Die." and Himegami falls over, dead.In a flashback, it is revealed that Himegami had always dreamed of being a magician, someone who saves the day with cool powers, like in the stories she read. Her dreams were killed when a vampire turned everybody in her village, including her mother. She was unable to do anything as they all rushed her in a feeding frenzy, only to be destroyed by her power.Aureolus mocks her and muses that he kept his promise after all, as powers don't work when the user is dead, so Himegami is finally rid of Deep Blood. Touma finally manages to touch his face and break free, then gets up and holds her in his arms. As soon as his right hand touches her, she gives a gasp and starts breathing again. Shocked, Aureolus says that's not possible. Touma carries Himegami to the side and says he will not allow Aureolus to do whatever he wants anymore.Touma charges at him, but Aureolus stabs himself in the neck and says, "Suffocate." Touma falls to his knees gasping for air, but he touches his neck with Imagine Breaker and the effect ends. Aureolus stabs himself again and says, "Be electrocuted." Lightning strikes all around Touma, but he blocks it all with his right hand. Aureolus stabs himself yet again and says, "Be crushed." A car materializes in midair and falls toward Touma, but he catches it with his right hand and it disappears.
Slightly impressed, Aureolus admits that Imagine Breaker can even negate Ars Magna. However, there is a simple solution: an attack too fast for Touma to block. He summons a 19th century pistol into his hand and fires into the wall, making a huge crater. The alchemist says he won't kill him quickly because he wants Touma to entertain him. He summons another gun, then modifies them so that they each have five barrels, connected in a fan-like array. He opens fire and Touma can't dodge. The bullets have the impact of paintball guns, so they don't kill him, but they really hurt. Aureolus laughs and says he wasn't kidding when he said he won't kill him quickly. He prepares to fire again.Stiyl, who is still pinned to the floor, speaks up and says something doesn't add up. Why didn't Aureolus just use Ars Magna to summon a vampire? Why did he need Deep Blood to attract one? Enraged, Aureolus causes Stiyl to be raised to the ceiling, then has him instantly flayed alive.Touma falls to his knees, clamping his hand over his mouth and trying not to throw up, but he begins to see what Stiyl was saying. If Ars Magna can be used to warp reality, why did he have to go through this vampire plan in the first place? Why didn't he just order Index to be saved? He concludes that Aureolus didn't believe he could save her with his own power. While he's thinking, Aureolus says Touma's right hand is powerful, but he is nothing without it, so he will rid him of it. He dismisses his guns and summons a rifle that launches swords. Even as he aims, Touma mutters that he has figured it out. Aureolus launches his sword. Touma stands still and it severs his right arm at the shoulder, with blood gushing everywhere.Aureolus laughs, but is cut off when, instead of screaming, Touma laughs with a completely deranged look on his face. Aureolus is horrified, wondering what is going on. Touma slowly marches toward him, still laughing. Scared, Aureolus launches another sword at his head, but it turns in midair and misses. Shocked, he modifies the sword launcher to have ten blades and fires them simultaneously, but they pass right through Touma without harming him. In desperation, he makes several guillotine blades materialize above Touma and orders them to fall, but they disappear right before they reach him. Touma asks him, "Hey Alchemist, did you really think you could get rid of my Imagine Breaker so easily!?"
Aureolus frantically reaches into his pocket for more needles, but he drops them. He tries to pick them up, and Touma mocks him, asking if he can't clear his head without them. Aureolus screams at Touma to stay away from him and runs away, hiding under the desk like a child. Touma continues to mock him, and Aureolus looks up to find Stiyl has gone back to normal. Touma says he figured it out, Aureolus' Ars Magna doesn't alter reality according to his words, but according to his thoughts. A massive dragon head emerges from Touma's right shoulder, and Aureolus screams as it opens its mouth and apparently swallows him whole.Touma wakes up in the hospital and is greeted by Heaven Canceler, who says he successfully reattached his right arm. The doctor remarks that it was surprisingly easy; all the muscles, nerves, and blood vessels fit together seamlessly, and he jokes that Touma must be a superhuman. He then comments that Touma has been in the hospital twice in such a short amount of time, and asks if he injured himself on purpose so he could flirt with the nurses. When Touma denies this, the doctor says he was hoping they had something in common and walks away. Touma is disgusted when he realizes the old man is a pervert.Stiyl comes in and peels him an apple, grudgingly thanking him for his help. Touma says he passed out right after the dragon attacked Aureolus, and asks what happened. Stiyl says Aureolus survived, but was so traumatized that he completely lost his memories. Knowing that the Roman Catholic Church wouldn't care about that and would demand his execution for what he did to the Knights, Stiyl took pity on him and used a spell to alter his face, then sent him out into the world to hopefully live a better life. In a sense, Aureolus Izzard is dead. Also, Misawa Cram School has been closed down for the time being. Touma asks where the dragon came from, and Stiyl says it must have been the embodiment of Aureolus' fears. However, Touma wonders if there was more to that, since it seems unlikely that a panicking man could imagine such a detailed dragon. Touma gloats about his masterful acting skills to unnerve Aureolus and make him believe his Ars Magna didn't work anymore, especially since he had to pretend losing his arm didn't affect him when in reality it hurt like Hell. Stiyl snarks that it wasn't that impressive, annoying him.Index comes in and Stiyl leaves. She was filled in to the situation and she says she's jealous that Touma was off to save Himegami instead of staying with her. Nonetheless, as it is a nun's duty to help others, she has invited Himegami to live with them until she can find a place of her own.In the anime, there is an additional scene where Himegami enters the room and thanks Touma, but asks why he would help a complete stranger like her. He repeats, "I don't need a reason to save someone." She is surprised and charmed. Index reveals she brought Sphynx, who jumps on Touma and scratches his face. As he complains and repeatedly presses the panic button to summon a nurse, Himegami smiles at the funny scene.