Saiga Ryuu

"I dedicate my life to you, and I will bring them all to hell—" The precious person in Kakeru's life, Ema, committed suicide. She was his only salvation, enduring cruel bullying daily. In his despair, Kakeru receives a "Bullying Victim Diary" which reveals a certain "truth." Knowing everything, Kakeru decides to dedicate his life to taking revenge on the bullies. Eighteen years later, Kakeru returns to his hometown, having attained status, wealth, a handsome appearance, and a strong physique. Now, let the class reunion begin—

The murderer is thirteen years old. Innocent and evil serial killer Shotaro appears! The job the boy chose was a serial killer. Killing, killing, killing! 100% violent crime suspense.