The Beginning Of The End/Owari no Hajimari

Let's talk about school bullying, cruel harassment, and the subsequent consequences. In the quiet hell of school, one boy becomes the victim of brutal bullying and systematic harassment at the hands of a group of classmates led by a charismatic but ruthless girl. But the real darkness begins much earlier. In the past, the protagonist's grandfather, the leader of a brutal gang of rapists and criminals, committed monstrous crimes that resulted in the death of his main tormentor's mother. Now, blinded by a thirst for revenge, she takes out all her hatred and pain on that very man's grandson, unaware or unwilling to know that he was not involved in those horrors.