Toaru Majutsu no Index Wiki

"Necessarius" (必要悪の教会ネセサリウス Nesesariusu?, lit. "Church of Necessary Evil") is the third episode of the first season of the Toaru Majutsu no Index anime series. It was first broadcast on October 19, 2008, and was directed and storyboarded by Tachibana Hideki and written by Akahoshi Masanao.

After Index's activation of "John's Pen", she and Touma had a narrow escape. The use of magic was required to treat Index's wound before she would have succumbed to it. However, due to the impact of the development of espers to gain abilities, they will get injured if they were to use magic. As such, Touma goes to Tsukuyomi Komoe's apartment for reliance, as she is merely a teacher and do not have esper abilities. However, even the recovery magic that would save Index will be negated due to the power that Touma's holds in his right had. As such, Touma has to wait outside the apartment of Komoe, though resents the fact that he cannot do anything. Index successfully recovers with the help of Komoe, and later, Index and Touma begin talking about magicians, magic books, and her own association with the circumstances that surround her, where she is forced to face pursuers by herself.


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In Komoe's house, John's Pen Mode Index asks Komoe of the local date and time, which she says is July 20th, 8:30 pm. Index asks if the time is accurate to which Komoe reply it is, as her internal clock goes by the second, Index confirms this by checking the position the stars and of the moon. Index later gets up and creates a pentagram inside a circle surrounded by symbols with her own blood. Index asks Komoe to help her and follow her instructions exactly, or else misfortune will befall them. Regardless, Komoe asks Index to stay put so she can contact medical assistance; however, Index says that they would be insufficient to treat her immediately. Komoe agrees to help her, and tells Index that she is not a magical girl; even then Index appreciates her assistance. However, time is running short and Index is coughing blood, she asks Komoe about the video game memory card and tells her to put it on the middle of the table. Later it is revealed to be used as a miniature model of the room they are in. The ritual begins, and Index asks Komoe to follow her instructions carefully or else she could die. They start by trying to summon an angel into the room and making a temple for it; Index asks Komoe to follow her singing, which she does. They keep singing, however, the table shakes making Komoe lose her concentration; regardless Index was able to create a link, with the model on the table as a temple linking to the room, and as such anything that will occur on the table will also occur in the room and vice-versa.

Index then tells Komoe to imagine a beautiful angel; she tries to do this but immediately loses concentration afterwards, however, she notices that the room is becoming distorted and she is sinking into the floor, causing her to panic. Index tells her that they are not actually trying to summon an angel, and tells her that as a mage she must create a form of an angel. Hearing this, Komoe tries her best at imagining a form of an angel and is successful at doing so, however it immediately dissipates. Index asks her to try again, Index sings while Komoe imagines a form of an angel, and are successful at doing so.The angel disappears and the glow from the table disappears as well, Index remarks that the healing is successful and comes out of her John's Pen mode. She loses balance but is held by Komoe, where she tells her that all that is needed now is rest. Index also remarks that she is thankful that she did not die, or else Touma would have shouldered it. Komoe asks if Index cares more about Touma than her well-being, to which she replies that she is unsure, she falls asleep before finishing her sentence to Komoe.

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The next day, Komoe asks Touma what his relationship with Index is, to which he replied is his sister, which was an obvious lie that Komoe picked up and enrages her, making Touma apologize for lying to her. Touma then asks her if Komoe is going to tell about Index to the Board of Directors, Komoe replies that since she is a teacher, it is her responsibility as one to take care of the problems that involves her students. She goes on to tell Touma that she is not going to stand-by and do nothing if Touma and Index were treading in dangerous ground. Touma tells her that if she was a stranger, he wouldn't hesitate in involving her but because Touma owes her a favor he doesn't want to involve her. This makes her blush and comments that even when he was trying to cover it up by saying cool words; it wouldn't help her forgive him. She later leaves to go out and do some shopping, and demands that they tell the truth when she returns; she however, notes that during shopping she might forget about it, and tells them not to play tricks on her when she returns.

Touma later takes care of Index, where they discuss of the dangers of using magic and where she tells Touma of the burden she is carrying. She tells Touma that she is from the Church of Necessary Evil or Necessarius, a religious organization that hunted witches because they were using magic and was considered evil, but the church needed magic as well to hunt them down, and as such they became the church they are today. Also, the reason why the church implanted the 103,000 grimoires into Index was to have them gathered into one spot and reverse-engineer them as so they can neutralize a type of magic. Touma is enraged on why Index kept this information to herself, which she replies that she didn't want Touma to hate her. Touma tells her that even when she has 103,000 grimoires inside of her, he would never consider her disgusting, and tells her not to judge people and have more faith in him.

Meanwhile, Stiyl and the long-haired magician from the previous episode are observing them. The long-haired girl remarks that Touma is neither a magician nor an esper, and cannot explain the mystery of his right hand. The girl remarks that Touma can be categorized as a "worthless student who likes to pick fights"; Stiyl remarks that there is an intentional black-out on his powers, and are surprised that Index's wounds were healed through magic. Stiyl calls the girl Kanzaki and asks her if there are any other magicians that are operating in Academy City. She replies that if there are, the city would have detected them. Stiyl later remarks on how Index and Touma seemed happy together and ambiguously asks how long they will have to keep destroying her happiness.

Touma later narrates on how Komoe returned and have not asked anything about anything and have allowed them to stay in her apartment. A few days later during night time, Index and Touma are travelling towards a bathhouse, when Index off-handily replies to an innocent question of Touma's; she states that she has no memories prior to coming to Japan, though she has memories of the fact that her name is Index, and that she has grimoires inside of her head, and the name of her church. Touma then asks her if she didn't even know the reason why she was losing her memories, which she confirms. Hearing this, Touma remains silent; however, Index misunderstands this as anger. They later get into an argument which makes Index bite her and run-away.

Touma is later seen trying to search for Index, however when he gets into an intersection, he notices that everybody has disappeared for no apparent reason. Suddenly Kanzaki holding her nodachi, appears before him and tells him that it is a rune that specializes in removing people in an area except them. She then introduces herself to Touma as Kanzaki Kaori.

Adapted From

Major Events


By order of appearance

New Characters

No new characters were introduced during this episode.


  • John's Pen Mode - Index

New Abilities

  • Healing Magic - Index and Tsukuyomi Komoe
  • People-clearing Field (A type of rune magic) - Stiyl Magnus


New Locations

  • the bathhouse where Komoe frequents (mentioned only)


  • The bath house where Komoe goes to is first mentioned in this episode. This is also the first time we see her gesture of drinking coffee milk after the bath, however it is not applied.
  • The Academy City Board of Directors is first mentioned in this episode.
  • This also the first time Imagine Breaker's secrecy is referred to, and is also the first time Touma is referred to as neither a magician or an esper.


No referbacks occurred during this episode.

Cultural References

  • Index references the clock tower in London, most likely the famed Big Ben.
  • Index mentions Cancer when drawing the pentragram on the table. Cancer is the fourth astrological sign in the Zodiac, and is considered a water sign.
  • Index references Undine twice in this episode during the ritual. They are water elementals, and maybe the reason why Index uses Cancer in her spell.
  • Index mentions the angel of Helheim, which maybe a reference to both the female being named Hel and the location Hel or Helheim, which she shares the name with in Norse mythology. Hel is an Old-Norse word that is derived from the Proto-Germanic *khalija, which means "one who covers up or hides something", while heim is a German word for home. The use of hel in Norse words implied that the word Hel referred to a common place of the dead.

Differences in Adaptation

Animation Trivia

  • During the scene on the rooftop, Kanzaki is not wearing her belt for no discernible reason, and neither Stiyl and Kanzaki commented on this.
  • During the scene on the rooftop, Stiyl seemed to have lost the rings he was wearing on both of his hands.


# Title Time Scene & Notes
Unverified Track Opening
Unverified Track
Unverified Track Eyecatch
Unverified Track
Unverified Track Ending
Unverified Track Preview

Unanswered Questions

  • If Touma is neither a magician or an esper, what exactly is he?
  • What is the power behind is right hand anyway?
  • Why is Stiyl troubled after seeing Index so happy?
  • Why is Index apparently able to do magic?


  • Komoe: "Then, what should I do? Sensei isn't a magical girl, you know?"-said to Index.
  • Index: "If I had died here, he might have needed to shoulder this."-said to Komoe, referring to Touma.
  • Komoe: "If I know that you are treading on dangerous ground, I am not stupid enough to just stand by and do nothing"-said to Touma.
  • Touma: "If you were a complete stranger, I wouldn't hesitate at all in involving you. But I owe you a favor, Sensei, so I don't want to get you involved."-said to Komoe as a reply to the above statement.
  • Index: "Do you want to know? Do you really want to know the burden I am carrying?"-said to Touma.
  • Touma: "What should I say? It's like I'm the Father now."-said to Index.
  • Touma: "Don't underestimate me. Just because you memorized 103,000 books, do you think I'd consider you disgusting? Have some faith in me. Don't be judging people on your own, okay?"-said to Index as a reply to her being scared if he knew the reason why she has 103,000 grimoires inside her.
  • Stiyl: "She seems really happy. She really does. She's been leading a happy life. How much longer do we have to keep tearing and ripping that up?"-said to Kanzaki, referring to Index and Touma.
  • Kanzaki: "Kanzaki Kaori is my name."-Kanzaki introducing herself to Touma.


This section requires expansion



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