Introducing herself as Kanzaki Kaori, the girl with the sword doesn’t want to reveal her magic name if she doesn’t have to. She claims to want to take Index into custody, but Touma refuses, so Kaori demonstrates her sword skill by cutting the blade off a wind turbine that’s a long distance away. She claims that her Nanasen ability allows her to kill seven times in an instant and that it’s a guaranteed kill. Right as Touma is thinking about using his right hand, Kaori reveals that she knows about it from Stiyl. Touma, however, still tries to charge at her and attack with it. She keeps him away with her Nanasen ability, and after a second failed attempt, Touma realizes that Kaori has super-thin wires deployed all around. Kaori explains that her katana isn’t for decoration and that getting past Nanasen would bring a technique called Yuisen. She then goes back to how she doesn’t want him to make her say her magic name, and despite his now injured right arm, Touma still tries to run at her. Kaori responds by hitting him in the gut with her sword sheath before kicking him to the ground.
Kaori doesn’t think that Touma has any reason to try this hard for Index, but Touma then questions why she hasn’t killed him yet. He recognizes how much power she has and feels that she can protect or save whatever she wants, so he doesn’t understand why she’s doing all this. Backing off a little, Kaori admits that she’s not doing this because she likes to, and she explains that she belongs to Necessarius, just like Index. In fact, Kaori calls Index a dear friend and claims that she didn’t intend to hurt Index – she only wanted to secure Index so that Index can live. The reason for all this is Index’s perfect memory ability. Kaori explains that the capacity of human brains are small, but forgetting unneeded memories is part of organizing the brain. Index can’t do that, so her memory is quickly filled with trivial stuff. With 85% of her memory devoted to the 103,000 magic volumes, the other 15% fills up quickly and needs to be erased or else Index will die. They do this every year, and there are only three more days before it needs to happen again.
Kaori then asks Touma once again to hand Index over and claims that helping Index has no benefit for Touma since she will just forget him. Touma, however, refuses to accept this and doesn’t care if Index remembers him because he still considers himself her friend. What he doesn’t understand is why Kaori doesn’t explain everything and clear up the misunderstanding with Index, and he thinks that she’s disregarding Index’s feelings. This pisses Kaori off greatly, and she lashes out on how Touma doesn’t understand how she and Stiyl feel. She channels her anger into attacks against Touma, and as she beats up on him, she claims that they did their best creating memories with Index and trying to keep her from forgetting, but it was no good. They got to the point where they couldn’t endure it, and they couldn’t bear to see her smile anymore. Touma’s reaction to all this is anger because he feels that Kaori and Stiyl weren’t considerate of Index. He feels that if they give her even happier memories in the next year, and if they can let her know that there’s happiness waiting for her such that she won’t be afraid of losing her memories, then there’s no need to run away anymore. Touma then tries to make Kaori realize that she became strong because she had something she wanted to protect, and before he loses consciousness, he questions who she wanted to protect.
Three days later, Touma wakes back up in Komoe’s apartment with Index watching over him. When he finds out how long he’s been asleep, he remembers what Kaori had said about three days, but since Index still knows who he is, her memory must still be intact. Touma is glad about this, but Index then expresses her feelings over how she didn’t know that he was fighting and couldn’t help him – Komoe was the one who had brought him back. In the subsequent conversation about his bandage, the topic of magic comes up, and Touma feels that not using magic is fine. He doesn’t want to see Index talking magic, and that causes her to realize that she woke up again. She’s not fond of her unconscious voice, and she’s scared that she’s becoming a cold machine. Index then tries to feed Touma, but she ends up spilling the food on his head. This all is interrupted by the arrival of Kaori and Stiyl at the apartment, but Index tries to make them go away and attempts to protect Touma by saying that she’ll do whatever they want.
Kaori doesn’t think that Touma has any reason to try this hard for Index, but Touma then questions why she hasn’t killed him yet. He recognizes how much power she has and feels that she can protect or save whatever she wants, so he doesn’t understand why she’s doing all this. Backing off a little, Kaori admits that she’s not doing this because she likes to, and she explains that she belongs to Necessarius, just like Index. In fact, Kaori calls Index a dear friend and claims that she didn’t intend to hurt Index – she only wanted to secure Index so that Index can live. The reason for all this is Index’s perfect memory ability. Kaori explains that the capacity of human brains are small, but forgetting unneeded memories is part of organizing the brain. Index can’t do that, so her memory is quickly filled with trivial stuff. With 85% of her memory devoted to the 103,000 magic volumes, the other 15% fills up quickly and needs to be erased or else Index will die. They do this every year, and there are only three more days before it needs to happen again.
Kaori then asks Touma once again to hand Index over and claims that helping Index has no benefit for Touma since she will just forget him. Touma, however, refuses to accept this and doesn’t care if Index remembers him because he still considers himself her friend. What he doesn’t understand is why Kaori doesn’t explain everything and clear up the misunderstanding with Index, and he thinks that she’s disregarding Index’s feelings. This pisses Kaori off greatly, and she lashes out on how Touma doesn’t understand how she and Stiyl feel. She channels her anger into attacks against Touma, and as she beats up on him, she claims that they did their best creating memories with Index and trying to keep her from forgetting, but it was no good. They got to the point where they couldn’t endure it, and they couldn’t bear to see her smile anymore. Touma’s reaction to all this is anger because he feels that Kaori and Stiyl weren’t considerate of Index. He feels that if they give her even happier memories in the next year, and if they can let her know that there’s happiness waiting for her such that she won’t be afraid of losing her memories, then there’s no need to run away anymore. Touma then tries to make Kaori realize that she became strong because she had something she wanted to protect, and before he loses consciousness, he questions who she wanted to protect.
Three days later, Touma wakes back up in Komoe’s apartment with Index watching over him. When he finds out how long he’s been asleep, he remembers what Kaori had said about three days, but since Index still knows who he is, her memory must still be intact. Touma is glad about this, but Index then expresses her feelings over how she didn’t know that he was fighting and couldn’t help him – Komoe was the one who had brought him back. In the subsequent conversation about his bandage, the topic of magic comes up, and Touma feels that not using magic is fine. He doesn’t want to see Index talking magic, and that causes her to realize that she woke up again. She’s not fond of her unconscious voice, and she’s scared that she’s becoming a cold machine. Index then tries to feed Touma, but she ends up spilling the food on his head. This all is interrupted by the arrival of Kaori and Stiyl at the apartment, but Index tries to make them go away and attempts to protect Touma by saying that she’ll do whatever they want.