Toaru Majutsu no Index Light Novel Volume 20 was first published on March 10, 2010. It marks the first usage of three-part novel storyline in the novel series. It is the first novel that depicts the events of World War III for the finale of the series. It gathers all three protagonist in the same novel for the first time since the first SS novel.
Russia declared the beginning of the Third World War.
The conflict between Academy City and Russia will expand to the level where it will involve all other nations. The ones behind the scenes manipulating it all are the last member of "God's Right Seat" and the bearer of the "Holy Right", Fiamma, and the man who watches and plans in secrecy, unknown to the rest of the world, Aleister Crowley.
In the fires of the World War, there is a group of people that runs to and fro.
The three of them holding three different thoughts, three different paths that should never meet, converge in Russia. And what awaits them there is…
- Prologue: The Sky is Filled with the Scent of Gunpowder — Shooting_Game.
- Chapter 1: Good and Evil, Their Respective Entrance into the Country — World_War_III.
- Chapter 2: The Start of Attack and Counterattack — Angel_Stalker.
- Chapter 3: The Stand-Off Against the Wall of Doubt — Great_Complex.
- Chapter 4: Now is the Time to Strike Back — Heroes_Congregate.
- Epilogue: Battle Report