Toaru Majutsu no Index Light Novel Volume 19 was first published on November 10, 2009. It deals with GROUP's and Hamazura Shiage's final efforts against the Dark Side of Academy City. The ending of the novel is concurrent with the ending of the previous one as a set-up for the finale of the series.
"GROUP". As it implies, it's a group of people dealing with incidents from the Dark Side of Academy City. Two members of the group—the strongest Level 5, Accelerator, and a man that's both an esper and a magician, Tsuchimikado Motoharu—teamed up to search about the mysterious keyword "DRAGON". It is believed that the keyword is the only hope to bring down the 'shitty' status quo of the present.
On the other hand, there is someone who found their activities, conducted without any permission from the higher-ups, a nuisance. The man would be a member of the highest authority in Academy City, the supervising Board of Directors. With his influence, he bares his fangs as a powerful obstacle to GROUP.
At the same time, the former members of "ITEM", Hamazura and Kinuhata, paid a visit to Takitsubo... Suddenly, Hamazura's "Doubt of Extreme Bunny Girl Enthusiast" broke out. Hamazura then desperately explains the situation to Kinuhata and Takitsubo who were drawn away to another place, but...?!
Continuing from Volume 15 and the SS series, the "Dark Side of Academy City" arc begins here!
- Prologue: The Uninteresting Exchanges Between Evil-doers — Key_Shop.
- Chapter 1: Goodwill Shall Be Trusted for Now — Dark_Hero.
- Chapter 2: A Simple, Yet Complicated Question — V.S._Calamity.
- Chapter 3: The Wider Path that is Opened by Destruction — Battle_to_Die.
- Chapter 4: The Two Monsters that Invite People to Hell — Dragon(≠Angel).
- Epilogue: Tragedy is Not the End — Brave_in_Hand.