Hara Okadai is one of the students in the institution.
Both his weight and most internal organs were stripped off of him, eventually making him rely on heavy medical support to prolong his life before the game could even end.
Hara Okadai stabbed a bully in his eye with a chopstick because they were picking on him for his weight.
Hara Okadai was a fat boy when young. He was called Fatty in elemantary school and to him, it seemed that to them, he was not human but a toy or an unknown organism. He treated it as a game as even though he was bullied but he wasn't ostracized.
When he went to Junior High, he thought that it would change but nothing happened and he still thought that even though he was bullied, he had a few friends.
And when he went to High School, he thought that it would be different and toughed it out. However, he realised that he was a bully victim and it would never change. When he was younger, he could forgive them as they were pranks but as they grew up, the bullying became worse.
On the day that he thought a girl named Tanaka would confess to him but instead, he overheard that they were just pulling a hurtful prank on him, as if making him think that he was 'delusional' for even thinking so. Enraged, he confronted the bullies who made fun of him and did the crime himself.