Kimizuka Chikara

In 1987, Tsuyoshi Otsuka fainted in a freak accident. Twenty-six years later, he miraculously wakes up. Now it's time for Otsuka to go back to school where he plans to live his youth with full force! There's just one problem: on the outside, everyone sees a 40-Year-Old man, while on the inside, he's still just a 14-Year-Old boy.

Kitami, a boy serving as class representative, is struggling to get a girl named Tojo — who transferred into the class in the middle of the semester — to fit in better with the class. But try as he might, his effort just goes nowhere. That's the situation when one day, a theft incident occurs in class. Tojo is suspected of being the culprit and becomes the target of bullying. Kitami desperately tries to stand up for her, but he gradually becomes isolated... (Source: Gangan Online)

Is corporal punishment by teachers strictly prohibited under any circumstances!? Sakurai, a teacher, witnesses bullying in her class and unintentionally raises her hand against the main culprit student, unaware that a disastrous future awaits them because of their resentment...

Angry voices and the cries of a girl can be heard from Room 502, on the floor above the room where I live. On television, tragic news reports are being broadcast about small children whose precious lives have been taken away by abuse. What if a similar tragedy is happening in Room 502? I may be the only one who can save the girl…

Aizawa was bullied by Suzuki to the point of becoming truant. He picks himself back up and becomes a teacher. 20 years later, his bully's daughter is one of his students and she's being harassed in class, a secret she keeps from her father.

It’s about a goodhearted boy named Takashi who murdered his teacher at age of 13, to protect his childhood friend Yui. The story revolves around tragedies happening to both of them because of that incident.