Toaru Majutsu no Index Light Novel Volume 15 was first published on January 10, 2008. It features for the first time an entire novel without Kamijou Touma appearing, and features both Accelerator and Hamazura Shiage as protagonist.
Chaos breaks out in Academy City when the city's underground organizations battle and race against time to obtain an important artifact before the others. In this volume it's completely Accelerator centered. We get to see various underground organizations such as GROUP, ITEM, SCHOOL, MEMBER, BLOCK. Volume 15 is also where we learn about Kakine Teitoku, the 2nd ranked level 5 who harbors extreme resentment towards Accelerator as he wanted to be used for the level 6 shift project. Many groups battle it out and many crumble. There are a lot of deaths in this volume and extreme foreshadowing such as Kakine figuring out what "awakening" is but before he can explain Accelerator smashes him into the ground. Mugino Shizuri also kills Frenda due to her being a traitor and trying to defect to SCHOOL. Hamazura takes out Mugino. GROUP was the only team left intact by the end of this volume.
The security forces in Academy City have all been deployed in Avignon as part of Academy City's invasion plan. The city becomes a lawless area of sorts, and organizations that belong to the darkness initiate their secret operations.
— One who moves only for himself.
— One who basks in the darkness and enjoys heartless slaughter.
— One who lives as a disappointment to others.
— One who fights on for the sake of someone precious.
— One who challenges others to reach the top.
— One who eliminates a certain rebel.
— One who holds back a rampaging streak of violence.
Science is now led into a certain path, and to survive...
When [GROUP]'s Level 5 Accelerator encounters the mysterious organization [SCHOOL], the story shall begin!
- Prologue: The Finest Lead Bullet for You, My Dear — Management.
- Chapter 1: An Unmistakable Gun, Unheard by All — Compass.
- Chapter 2: The People Who Have Slowly Begun To Move — Hikoboshi_II.
- Chapter 3: In the Land of Sealed Powers — Reformatory.
- Chapter 4: The Paper-Thin Difference Between Self-Derision and Pride — Enemy_Level5.
- Chapter 5: Defeat the Person with the Strongest Black Wings — Dark_Matter.
- Epilogue: The Victory Prize for Those Who Survived — Nano_Size_Data.