World War III Arc

World War III (abbreviated WWIII or WW3, also referred to as Third World War) is a global war that lasted from October 19 to October 30 of the current year of the Toaru Majutsu no Index timeline, as well as its last story arc, spanning Volumes 20, 21 and 22. Although lasting briefly, the war mostly involved two opposing great powers and alliances of Academy City, against the Russian Federation, controlled by the Roman Catholic Church.

The Roman Catholic Church, under the influence of God's Right Seat, manipulated events in order to ensure Russia's alliance with it, specifically that of the Russian Orthodox Church. France sided with the Roman Catholic Church due to its long held animosity against the United Kingdom of Great Britain and Northern Ireland, who were allies of Academy City.

The United States of America were the only ones left out. As they were gearing up for it, the war ended before they could pick a side.

However, the war was actually part of the plan of Fiamma of the Right, manipulating the great Churches and even God's Right Seat to do his bidding.

Due to the forces that are composed in the war, it marks the first conflict that both the Magic and Science Sides have been trying to prevent since even before the start of the story.

The story arc focuses on the three protagonists, Kamijou Touma, Accelerator, and Hamazura Shiage, heading deep into Russia in order to save the one they hold dear just as the entire world plunges into a Third World War. In order to save Index, Touma is hunting down the leader of God's Right Seat Fiamma of the Right, the man who stole the spiritual device that controls Index and now has sparked a global conflict in order to fulfill his ambitions.

Academy City–Roman Catholic Church Cold War
Although Lidvia Lorenzetti's plans to take over Academy City using the Croce di Pietro were apparent before any obvious animosity existed between the City and the Church, the start of the cold war began after the events of Orsola Aquinas' rescue. That is due to the fact that the Roman Catholic Church was weakened due to the events of this arc. With the destruction of their main fighting strengths Gregorian Chant and the Agnese Forces, as well as the Anglican Church gaining the Amakusa Christians, the Roman Catholic Church was put in a vulnerable enough position in allowing Lidvia Lorenzetti to set-up the Croce di Pietro in Academy City, to tip the already crumbling balance between the world's factions into their favor.

Takeover attempt on the Daihaseisai
A rather non-violent attempt at taking over Academy City was implemented by Lidvia on September 19 of the current year of the timeline using the Croce di Pietro. Despite her efforts however, the plan is foiled and both she and her hired mercenary, Oriana Thomson are later detained by the Church of England. With their failure and with the Croce di Pietro lost, the events of September 19 would force the Roman Catholic Church to opt for the total destruction of Academy City instead of capturing, by reviving an ancient weapon of the church, The Queen of the Adriatic Sea.

Mobilization of the La Regina del Mare Adriatico
Although violent, the main conflict between Academy City and the Roman Catholic Church could have been prevented by the usage of the antiquated La Regina del Mare Adriatico, which could utterly destroy all of the science side in a single blow. However, after the Battle of the Adriatic Sea, the La Regina del Mare Adriatico and its Queen's Fleet were destroyed, Biagio Busoni was captured, and a powerful group of nuns, the Agnese Forces, later defected to the Anglican Church.

The event severely weakened the Roman Catholic Church and further strengthened the Anglican Church. The failure of the act and the presence of Kamijou Touma in several events were the Roman Catholic Church failed in their endeavors sealed the fate of a world in conflict.

0930 Incident
Roman Catholic Church forces later tried to strike a preemptive blow to Academy City through the direct attack by Vento of the Front. Many citizens of Academy City and most likely the rest of the world were affected by Vento of the Front's Divine Punishment, which would've been used as the opening for the Roman Catholic invasion forces to impale the citizens of Academy City.

The main goal of the invasion was to assassinate Kamijou Touma, who by now, has become the core of the conflict between the two forces, as an enemy of God and quickly take over Academy City before it can counter-attack. This would have most likely prevented a war with Academy City and its allies.

However, the plan fails with the defeat of Vento of the Front and the destruction of the Roman Catholic invasion forces. With the appearance of Fuse=KAZAKIRI and the blatant usage of magic of the Church, conveniently covered up as an outside esper program, both sides criticize each other's claims, and later demands of concessions and compromises could not be reached.

Anglican Church–Russian Orthodox Church Prewar Conference
The two great Churches of Europe met in London in St. George's Conference to discuss their stance of the upcoming war. The meeting was inconclusive apparently as the Churches could not decide who to ally with, and in the end the Anglican Church remained loyal to Academy City while the Russian Orthodox Church seemed neutral.

Declaration of War
Prior to the start of the war, the President of Russia, I. Krainikov, declared war on Academy City:

"Now is the time for efforts to protect the world and all of mankind who fight to continue living in this world."

"In today's world all of humanity faces similar crises: The greenhouse effect, rising sea levels caused by environmental damage, and the shortages of oil and other fossil fuels. All such world-wide events are the result of a single culprit: Academy City of Science and Technology. If we do not put a halt to their continuous abuse of science and technology in such a disorganized manner, then this planet, and all who live in it, will face extinction."

"To protect our common humanity, and the future of all forms of life on this planet, Academy City ought to halt all projects and pursuits currently undertaken. Moreover, in order to analyze and solve problems common to all walks of life, I hereby demand the holder of the most advanced technology on this planet give full access of that technology to myself."

"Despite continuous pursuit of a peace proposal, Academy City has mercilessly rejected all such attempts. Such rejection demonstrates that Academy City continually defies integration into the global community. I had planned to wait until determining their purpose and the motivation behind it, but to live on this planet while it is in crisis, a crisis that exposes all forms of life to the existence of evil, is something I will not tolerate."

"I will wait until 0:00 Moscow Standard Time on October 19 for Academy City's reply. If they have not submitted their answer by such time, I will interpret their lack of response as a declaration of war, and will immediately consider the use of offensive engagements with intercontinental ballistic missiles."

"Furthermore, I will consider the friendly relations Academy City currently maintains with Great Britain and Northern Ireland, and making similar judgments. If Academy City continues to insist on selfishly pursuing their own interests and, moreover, ignoring the plight of all outside forms of life, I shall recognize them as an enemy. For our posterity and the posterity of all future generations, we shall fight them wholeheartedly."

"October 18, Great Command of the Russian Federation, Soldier I. Krainikov" 

Battle of Dover Strait
After discovering the premature deployment of French ships during the British Civil War, England manages to anticipates the attack of French forces from Dover Strait, and prepared ships against them for a naval battle. However, they did not expect that the French forces would freeze the waters of the Strait and turn into a battlefield. Despite the fragile surface of the battlefield, the Anglican Church forces, composed of the Amakusa-Style Remix of Church led by Kanzaki Kaori and the Agnese Forces led by Agnese Sanctis, engage the magicians of the French forces. They are later aided by the reactivation of the Curtana by Queen Elizard and the arrival of the Knights of England, accompanied by its leader, and second princess Carissa.

The British forces take much ground against the French forces until the arrival of the Maiden of Versailles, which forces Carissa to clash against her and use the mobile fortress Glastonbury. The battle prematurely ends once the Golden Arms start appearing and the forces begin rushing towards Russia.

Central Front
At first, Russia attacked Academy City with ballistic missiles; but this was unsuccessful because all the missiles were derivatives, made by intercepting weapons in Academy City.

Within its borders, Russia deployed many units to defend itself. Many civilians in villages near the border were forced to evacuate their homes and were mobilized by magicians and the Russian military. Also, the government contracted mercenaries to monitor some border areas and attack some villages considered "problematic". Still, the Russian troops were defeated by the advanced military technology from Academy City, on many fronts. The Russian Air Force was no match for its enemy's supersonic bombers. This overwhelming vantage allowed Academy City to establish many bases within Russia.

Proclamation of Armistice
"We can't let this meaningless war continue."

"Our side has clearly examined the conditions proposed by Academy City, and we will continue to discuss this. We'll negotiate about the details, but we can assure that Russia will not end up disadvantaged."

"In the past, we ignored the advice of the public, followed the suggestions of a few people and were unable to undo our choice. As for how tragic the situation was, I suppose everyone knows it better than I do. Regarding this historical error, we can't make any excuses."

"At least what I can do is to end all these abnormal situations as soon as possible, and let the world regain the peace that it should have had."

"Before all of these end, we shall be punished."

"So before that, please give me some time."

"A minority may be unhappy with this result, and may feel that putting down our arms isn't what we should do. However, I want everyone to calm down and think: what were we fighting for? If it's to fight for our family, our friends, our lovers, all the people that are important to us, this is the time, the moment to get all of 'these'. Continuing to fight on will only cause you to lose 'these'."

"The thing that made us recognize this were the actions of everyone on the battlefield."

"Facing the supernatural disaster near the end of the war, we chose a 'correct' move that's way above us, helping everyone, enemies and allies, without any difference. I believe that we can accept this ending."

"From now on, I declare that all fighting will cease. I hope for everyone to agree with this decision, and will be recorded for a future peaceful world to see."

"30th October, Archbishop of the Russian Orthodox Church"

"Krans R. Tsarskiy" 

Aftermath

 * Destruction of God's Right Seat
 * Change of Pope for the Roman Catholic Church
 * Kamijou Touma declared MIA
 * Disbandment of the organizations of the Dark Side of Academy City
 * Restructuration of ITEM
 * Revelation of Aleister Crowley's survival to the whole world