Toaru Majutsu no Index Light Novel Volume 16/Chapter 4

Synopsis
The commotion outside about a lack of air in District 22 caused many of the people to evacuate the nearby buildings. Although the alert has been lifted, many people, including Misaka Mikoto, ended up disgruntled by the sudden emergency. On her way to a hotel in the seventh level of the district, she sees a spiky-haired boy wearing a patient's hospital gown and finds out that it's Kamijou Touma, who seems to have escaped from some hospital after receiving grave injuries. After supporting his limp body, Mikoto reveals that she knows about his memory loss and that she wanted to help Touma in one way or the other. This revelation did not stop Touma from pushing on, however. Mikoto helplessly watches as Touma heads out to parts unknown.

Elsewhere, Kanzaki Kaori is slowly realizing the limits of her body as she was unable to defeat Acqua of the Back using one blow of her Yuisen. Severely weakened, Kanzaki was forced on the defensive as Acqua continues to pummel down the Saint of the Far East. However, she refuses to believe that powerless people are unfit for a battlefield as Acqua had explained, especially after seeing a powerless boy's many struggles. Soon, after realizing what she had to do, Kanzaki calls out to her former comrades to help her in the fight against Acqua of the Back.

Although shocked by Kanzaki's unexpected plea, the Amakusas pick up their weapons and stood up despite their injuries. Afterwards, they leapt to Kanzaki's side, leaving Acqua dumbfounded. Acqua continues on his assault against Kanzaki and the Amakusa, but they already have the Saint Destroyer spell prepared for Acqua, confident that this attack will cause Acqua to self-destruct due to his nature as a Saint and his Divine Mother's Mercy. Regardless, Acqua unleashes an aerial attack that he aims to destroy Kanzaki and the members of the Amakusa Church. Kanzaki prepares to defend her comrades from the attack, but Acqua's attack dissipates at the right hand of Kamijou Touma, who arrives at the critical moment. Then, as Kanzaki pins down Acqua, Itsuwa is left to strike the Saint Destroyer directly onto Acqua. Unlike the failed attempt before, Acqua was successfully hit by the spell, and his body explodes under the reaction of the spell, creating more havoc in the process.

Between the Lines
Although the third princess of England was rescued successfully, Knight Leader wasn't happy to see William Orwell disobey his request. What further worsened his temper was William Orwell's decision to leave England. However, William explained that he needed to leave England so that he could observe the Knights of England from an outside perspective, especially with several powers outside England moving at their own pace. After asking Knight Leader to watch over the knighthood from his side, the two friends part ways, with Knight Leader seemingly disappointed that William had thrown away their friendship with such ease.

Adapted To

 * Anime: Toaru Majutsu no Index III Episode 09
 * Manga: Toaru Majutsu no Index Manga Chapter 161, Chapter 162 and Chapter 163 (Between the Lines 4)

Characters
By order of appearance
 * Misaka Mikoto
 * Kamijou Touma
 * Acqua of the Back
 * Kanzaki Kaori
 * Tatemiya Saiji
 * Itsuwa
 * Knight Leader

New Characters

 * Villian

Abilities

 * Saint Destroyer

Locations

 * Academy City
 * School District 22

Cultural References

 * When the Knight Leader gives a bottle to William Orwell, he attributes the drink to "Chamberlain" (チェンバレンのじいさん).
 * The is a  who acts as the senior executive officer of the Royal Household and manages the departments that support the monarch and the royal family.
 * It is assumed that the Knight Leader is referring to the individual acting as Lord Chamberlain of the Royal Household at that point in-universe, however it should be noted that  is also a family name.